At the conclusion of a twelve-day trial, a jury convicted 'defendants-appellants José Ramón Caraballo-Gonzalez and Victor Le-brón-Cepeda of committing and aiding and abetting each other and others in the commission of a carjacking resulting in a death, see 18 U.S.C. §§ 2119(3) and 2, and of using and carrying, and aiding and abetting each other and others in the use and carriage of, a firearm during and in relation to the carjacking, see 18 U.S.C. §§ 924(c)(l)(3) and 2. The district court subsequently sentenced each defendant to life imprisonment for his carjacking conviction and to a statutorily mandated five-year consecutive term of imprisonment for his firearm conviction. Defendants appeal these judgments on a number of grounds. We affirm.
I. Background
We start with an account of the facts of the crimes as the jury could have found them, e.g., United States v. Diaz, 285 F.3d 92, 94 (1st Cir.2002), but defer providing certain additional information until we discuss the issues to which the information is relevant.
At about 11:40 p.m. on March 23, 1996, Iván Fontánez-Bruno, a Puerto Rico Police Department cadet, drove his 1994 Hyundai automobile into a parking lot in a park adjoining a beach in Figwort, Puerto Rico. Daisy Torres-Muñoz, a fellow cadet whom Fontánez was dating, was seated next to him in the front passenger seat. Fontánez and Torres had their police-issued firearms with them. Torres was carrying her weapon, but Fontánez had placed his in a black bag between the seats and next to the emergency brake.
As the automobile entered the lot, Torres noticed appellant Caraballo, co-defendant Harold Evans-Garcia (who was tried separately, see United States v. Evans-Garcia, 322 F.3d 110, 2003 WL 1240599 (1st Cir.2003)), and a third man she never was able to identify (but ydiom other evidence showed to be appellant Lebrón) sitting on some nearby rocks. The three earlier had split from a larger group of individuals (all of whom were named as co-*55defendants) with the shared intention of committing a carjacking. Ail three knew that, just prior to the carjacking, Caraballo was armed with a nickel-plated .38 caliber revolver that would be used to facilitate the contemplated carjacking.
Fontánez parked his car next to a light pole along the beach front and turned it off. The car’s windows were down. Fon-tánez and Torres began to talk about the driver’s licenses they would need in order to drive patrol cars for the police force. As they were talking, Torres opened her purse and, after placing her gun between her legs, set her purse down on top of it in order to retrieve her driver’s license. Periodically, Torres looked out the Hyundai’s rear window at the individuals on the rocks because the way they were studying the cars in the lot aroused her suspicion.
Eventually, Torres mentioned her concern about the individuals to Fontánez and suggested that they leave. Fontánez turned to start the ignition and drive off, but was unable to do so because the three men had surrounded the car. Caraballo and Lebrón approached on the driver’s side window, while Evans-Garcia approached on the passenger’s side. Cara-ballo thrust the revolver through the window and placed it against Fontánez’s head. Fontánez removed his gun from his bag, but Caraballo warned Fontánez against using it, stating that his revolver was cocked. Fontánez dropped the gun.
Caraballo, Evans-Garcia, and Lebrón pulled open the car doors and ordered Fontánez and Torres, who was concealing her gun beneath her purse, to move into the car’s backseat. Fontánez and Torres complied and took seats facing each other, with Fontánez in the middle and Torres on the driver’s side. Caraballo handed his revolver to Lebrón and took the wheel; Evans-Garcia picked up Fontánez’s weapon and sat in the front passenger seat; Lebrón seated himself in the rear on the passenger’s side and placed the revolver against Fontánez’s head. After warning Lebrón to be careful because the revolver was cocked, Caraballo drove away.
At some point, Evans-Garcia accused Fontánez of being a police officer because only an officer would have a weapon like the one Fontánez had dropped. Fontánez denied being a police officer and claimed that he worked for Wells Fargo. Fontá-nez and Torres begged to be released and offered to give the three assailants money and to drop them off wherever they wanted. One or more of the assailants replied to the effect that Fontánez and Torres would not be released and should know that they were “on [their] way to the cemetery.” 1 The three also robbed Fontánez and Torres of money and jewelry but were dissatisfied with what they found. Lebrón returned Torres’s jewelry to her.
Shortly thereafter, under the guise of putting on her sandals, Torres placed her gun under the seat in front of her in a place where she could grab it should the need arise and the opportunity present itself. After she sat back up, Torres placed one of her feet on top of the gun. But almost immediately, Caraballo drove the car into something that caused one of its bumpers to become detached and to be dragged along the ground. The impact *56caused Torres to inadvertently kick the gun to a spot beyond her reach. Moments later, apparently after discovering something that identified Fontánez as a police officer, Evans-Garcia yelled, “I told you. I told you that this son of a bitch was a cop.” Lebrón immediately shot Fontánez once in the head, and Evans-Garcia turned around and shot him seven more times.
Following the shooting, Caraballo made a U-turn and stopped the car. He and Lebrón exited and pulled the rear bumper completely free from the chassis, removed Fontánez’s body, and dumped it on the road next to the car. Evans-Garcia pulled Torres from the car by her hair and, after a brief argument among the carj ackers about whether to kill her as well, Lebrón told her to run. Torres jumped over a barrier next to the road and watched as the car drove off. Torres then ran to a nearby business and persuaded a patron to call the police. A patrol car arrived almost immediately. Torres gave one of the responding officers a description of the Hyundai and a brief description of its occupants. She also made the officer aware of the direction in which the car had departed. The officer communicated this information to other police officers via his police radio.
At about 12:15 a.m. on March 24, 1996, Carlos Martinez-Rivera, a marshal in the Puerto Rico court system, observed a red car with a missing bumper come to an abrupt stop in front of him. He saw Cara-ballo, Evans-Garcia, and a third man whom he was not able to identify (but whom other evidence showed to be Le-brón) exit the vehicle and walk quickly in the direction of a nearby housing project. Regarding what he had seen as suspicious, Martinez went to his nearby residence and called the police. He learned about the carjacking and murder. Martinez returned to the red car and gave a police officer who arrived at the scene a description of its occupants. He also pointed out the housing project towards which they had been headed. The officer passed the information along to other officers. A short time later, the police arrested Cara-ballo and Evans-Garcia at the housing project. Lebrón escaped arrest that night and fled to New York, where he was apprehended on April 13,1997.
II. Discussion
Caraballo and Lebrón together challenge the sufficiency of the evidence underlying their carjacking convictions and, by extension, the sufficiency of the evidence underlying their firearms convictions. Caraballo alternatively argues that his convictions were tainted by the district court’s erroneous admission of out-of-court and in-court identifications of him by witnesses Torres and Martinez; by the court’s plainly erroneous admission under Fed.R.Evid. 801(d)(2)(A) of certain out-of-court statements of Lebrón which tended to inculpate Caraballo; and by the court’s denial of his motion for a mistrial when a witness testified that Lebrón had told him that Caraballo shot Fontánez. Lebrón alternatively contends that the court erred in applying the first degree murder cross reference specified in U.S.S.G. § 2B3.1(e)(l); in declining to award him a role-in-the-offense downward adjustment; in computing his criminal history category; and in declining to order that his court-appointed trial counsel be reimbursed for expenses incurred in flying a court-authorized defense witness from Washington, D.C. to Puerto Rico in order to testify at trial. We address each of these arguments in turn.
A. Sufficiency Arguments
Caraballo and Lebrón together assert that the evidence was insufficient to sup*57port the jury’s determination that they had the mens rea required by 18 U.S.C. § 2119.2 Relying upon a portion of the penultimate sentence of Holloway v. United States, 526 U.S. 1, 12, 119 S.Ct. 966,143 L.Ed.2d 1 (1999) (“The intent requirement of § 2119 is satisfied when the Government proves that at the moment the defendant demanded or took control over the driver’s automobile the defendant possessed the intent to seriously harm or kill the driver ....”) (emphasis supplied), they say that the evidence was inadequate to ground a finding that they were prepared to seriously harm or kill Fontánez prior to learning that he was a police officer— which happened only after they had taken control of his automobile. The government’s response is built from the remainder of the sentence appellants quote, which says that a conditional intent to seriously harm or kill the driver “if necessary to steal the car” is sufficient to satisfy the statute. Id. In the government’s view, the evidence was adequate to support a determination that appellants were prepared to seriously harm or kill Fontánez in the beach parking lot had he resisted their initial demand for his car.
The evidence that Caraballo placed a loaded and cocked revolver against Fontánez’s head at the inception of the carjacking and verbally threatened him permitted the jury to infer that Caraballo would have shot Fontánez had Fontánez failed to comply with Caraballo’s demand that he turn over the car. See Evans-Garcia, slip op. at 8; cf., e.g., United States v. Adams, 265 F.3d 420, 424 (6th Cir.2001) (evidence sufficient to support intent finding where the defendant threatened and then physically touched the victims with his gun); United States v. Lake, 150 F.3d 269, 272 (3d Cir.1998) (evidence sufficient to support intent finding where defendant placed a gun near the head of the victim and asked for her keys). Moreover, the evidence that Lebrón willfully and knowingly participated in the initiation of the carjacking while fully cognizant of how Caraballo intended to (and did in fact) use the revolver permitted the jury to draw the same inference as to him. See Evans-Garcia, slip op. at 8. Because the evidence was sufficient to permit the jury to draw these inferences, it was adequate to ground its determination that appellants took the vehicle with the required mens rea. See id.; see also Holloway, 526 U.S. at 12,119 S.Ct. 966.3
*58In his brief, Lebrón makes an additional sufficiency argument. Lebrón starts by asserting that the evidence pertaining to his role in the offense derived solely from out-of-court, post-offense confessions he made to a number of third parties, which the third parties recounted to the jury (and which were admissible against Le-brón as admissions under Fed.R.Evid. 801(d)(2)). Building from this base, Le-brón contends that the accounts of his various confessions that the jury heard so conflicted with one another that we should treat them as inadequate to sustain his conviction. In pressing this claim, Lebrón invokes “[t]he general rule that a jury cannot rely on an extrajudicial, post-offense confession, even when voluntary, in the absence of ‘substantial independent evidence which would tend to establish the trustworthiness of the statement.’ ” United States v. Singleterry, 29 F.3d 733, 737 (1st Cir.1994) (brackets omitted) (quoting Opper v. United States, 348 U.S. 84, 93, 75 S.Ct. 158, 99 L.Ed. 101 (1954)). The argument fails for several reasons.
First, if Lebrón understands the trustworthiness requirement to apply where the issue is the credibility of witnesses’ testimony about an accused’s confession — and not the credibility of the confession itself— he is mistaken. The trustworthiness requirement is imposed out of concern that people sometimes fabricate stories about their involvement in a crime, and accordingly requires the government to introduce evidence other than the confession which tends to prove that the confession was not such a fabrication. See id. at 736-37 & n. 3. But to the extent that the in-court testimony about an extra-judicial confession may be unreliable, that is a matter for cross examination. Second, this circuit has not decided whether the trustworthiness requirement constitutes grounds for launching a sufficiency challenge (as Le-brón has done) or acts merely as a rule governing the admissibility of evidence. See id. at 737-39 & nn. 4-6. Finally, and perhaps most importantly, Lebrón is wrong in stating that there was no evidence against him except that derived from what he told third parties about his role in the crime. Among other things, Torres’s testimony about the tragic events that transpired in Fontánez’s Hyundai constituted independent proof of the commission of the charged offense and was more than sufficient to establish the trustworthiness of Lebrón’s confessions within the meaning of the rule he cites. See id. at 737 & n. 2.
B. Caraballo’s Alternative Arguments
1. Identification Evidence
Martinez arrived at the scene of Cara-ballo’s arrest within minutes of its occurrence and, without a request from the arresting officers, identified him as one of the three men about whom he had telephoned the police. Torres identified Cara-ballo in a photo spread of six photographs held on April 4, 1996, one and one-half weeks after the carjacking. Prior to trial, Caraballo moved both to suppress these out-of-court identifications (usually admissible under Fed.R.Evid. 801(d)(1)(C)) and to prohibit Torres and Martinez from identifying him in court. Caraballo argued that the procedures by which the identifications were procured were impermissibly suggestive, and that the suggestiveness was such that there was a very substantial likelihood of irreparable misidentification. See Simmons v. United States, 390 U.S. 377, 384, 88 S.Ct. 967, 19 L.Ed.2d 1247 (1968) (setting forth the two-part standard under which the appropriateness of suppression is to be judged). In support of *59his motion, Caraballo pointed out that Martinez saw Caraballo handcuffed and sitting in a police cruiser prior to identifying him. Caraballo also introduced evidence tending to show that Torres saw Caraballo in a holding cell when she was brought to the same police station at which he was being detained a few hours after the carjacking (a sighting which Torres denied).
Following a five-day hearing, the district court issued a written order denying Cara-ballo’s motion. Applying the inquiry mandated by Simmons, the court first held that the procedures that the police employed were not impermissibly suggestive. With respect to Martinez, the court found that the police did not use suggestive procedures “because [Martinez’s identification of Caraballo] was contemporaneous with the events that the witness had seen only a few minutes before and because it was precisely the information that he provided to the police that led to [Caraballo’s] arrest.” As to Torres, the court implicitly credited Torres’s testimony and found that she did not see Caraballo in a holding cell prior to identifying him in the photo spread.
On appeal, Caraballo asserts that “there can be no question” that the district court erred in concluding that the circumstances under which Martinez identified Caraballo were unduly suggestive. But this ipse dixit is neither elaborated nor bolstered by citation to applicable authority. Mindful that a court is to withhold identification evidence from the jury only in “extraordinary circumstances,” United States v. de Jesus-Rios, 990 F.2d 672, 677 (1st Cir. 1993) (citation and internal quotation marks omitted); see also United States v. Maguire, 918 F.2d 254, 263-64 (1st Cir. 1990) (emphasizing that the suggestiveness of an identification procedure is a proper subject of cross examination and that the jury is usually competent to weigh intelligently questionable identification testimony) (citing Manson v. Brathwaite, 432 U.S. 98, 116, 97 S.Ct. 2243, 53 L.Ed.2d 140 (1977)), this assertion is inadequate to put the court’s conclusion into issue, see United States v. Zannino, 895 F.2d 1, 17 (1st Cir.1990) (“[I]ssues adverted to in a perfunctory manner, unaccompanied by some effort at developed argumentation, are deemed waived.”). At any rate, our independent review of the matter satisfies us that the court permissibly allowed the jury to hear about Martinez’s identification of Caraballo.
With respect to Torres, Caraballo essentially contends that the evidence that Torres saw Caraballo in a holding cell a few hours after the carjacking was so powerful that the district court erred in crediting the accuracy of Torres’s contrary testimony. We uphold a denial of a motion to suppress if any reasonable view of the evidence supports the denial. See United States v. Watson, 76 F.3d 4, 6 (1st Cir. 1996). As an appellate court, we lack the competence and authority to second-guess the court’s decision to credit Torres. See, e.g., United States v. Laine, 270 F.3d 71, 75 (1st Cir.2001). And in any event, as with Martinez, our independent review of the issue leads us to conclude that the court reasonably allowed Torres’s identification of Caraballo to go the jury.
2. Prejudicial Spillover from the Case against Lebrón
As set forth above, the jury heard several witnesses recount the details of admissions Lebrón made to them about his role in the carjacking. Caraballo did not seek a severance of his trial or a limiting instruction informing the jury that these admissions were not to be considered against him. Caraballo now contends that the admissions described facts so similar to those *60for which he was on trial that the district court’s failure to sever his trial from Le-brón’s or to give the jury a limiting instruction amounted to plain error within the meaning of Fed.R.Crim.P. 52(b). Car-aballo analogizes his plight to that of the accused in United States v. Sauza-Martinez, 217 F.3d 754 (9th Cir.2000), which found plain error in a trial court’s failure to give a limiting instruction at the time it admitted evidence regarding an extra-judicial statement by the accused’s co-defendant that directly implicated both the co-defendant and the accused. See id. at 759-61. Caraballo also complains that the court erred in denying his motion for a mistrial when one of these witnesses testified that Lebrón told him that Caraballo (and not Lebrón) had shot Fontánez.
While it would be most unusual for us to find that a district court erred in failing to give a limiting instruction that was never requested, we shall assume solely for the sake of argument that the court should have instructed the jury sua sponte that Lebrón’s admissions were not to be considered against Caraballo. Even so, the hurdle set by Fed.R.Crim.P. 52(b) is high. See Olano, 507 U.S. at 732-37, 113 S.Ct. 1770. And here, Caraballo has fallen far short of demonstrating that any error was of a type subject to correction under Rule 52(b).
There never was any doubt that three men participated in the carjacking and killing at the heart of this case. The case against Caraballo thus did not turn on what happened; it largely turned on whether the government had proved beyond a reasonable doubt that Caraballo was one of the three men who committed these crimes. In the end, the jury almost certainly credited Torres’s testimony that Caraballo was one of the three men, and Martinez’s testimony that Caraballo was one of the three men whom he saw exit Fontánez’s Hyundai shortly after the carjacking. Lebrón’s admissions — which with the exception discussed below never identified Caraballo as one of Lebrón’s co-perpetrators (which distinguishes Caraballo’s situation from that of the defendant in Sauzar-Martinez, see 217 F.3d at 761)— almost certainly had no bearing on the jury’s decision to credit this testimony. The absence of a limiting instruction thus did not affect Caraballo’s substantial rights. See Olano, 507 U.S. at 735, 113 S.Ct. 1770.
By contrast, the testimony that spurred Caraballo’s motion for a mistrial did identify Caraballo as one of Lebrón’s co-perpetrators. But as we have recently explained: ‘When a witness strays into forbidden territory, the usual remedy is to strike the wayward remark and instruct the jury to disregard it.... In all but the rare case, that remedy, if properly executed, will suffice to safeguard the aggrieved party’s rights.” United States v. Lee, 317 F.3d 26, 35 (1st Cir.2003). Here, as in Lee, the district court promptly struck the testimony and instructed the jury to ignore it. And here, as in Lee, the court’s refusal to order a mistrial was within its discretion. See id. Factors similar to those mentioned by the Lee panel in support of its ruling guide our analysis.
First, the witness’s reference to Cara-ballo was largely cumulative of Torres’s far more direct and damning testimony that Caraballo was one of the carjackers and Martinez’s testimony that Caraballo was one of the men who exited Fontánez’s Hyundai. See id. True, Torres did not identify Caraballo as a shooter, as did the witness. But from the jury’s perspective, the identities of the shooters were immaterial to whether they were guilty of the carjacking and weapons charges for which they were indicted. Second, the remark appears to have been entirely accidental *61and was in no way invited by improper government questioning. See id. Third, the district court quickly struck the remark and told the jury to disregard it in language with which Caraballo has never taken issue. See id. Finally, the record provides no reason for us to disregard the presumption that jurors follow their instructions. See id. In sum, here (as in Lee), the errant comment, while unfortunate, was not a difference maker.
C. Lebrón’s Alternative Arguments
Lebrón’s alternative arguments do not require extended discussion. His first argument is that the district court erred in applying the first degree murder cross reference set forth at U.S.S.G. § 2B3.1(c). This guideline directs the sentencing judge to apply the guideline for first degree murder, U.S.S.G. § 2A1.1 (setting a base offense level of 43, which requires a life sentence irrespective of defendant’s criminal history), “[i]f a victim was killed under circumstances that would constitute murder under 18 U.S.C. § 1111 had such killing taken place within the territorial or maritime jurisdiction of the United States....” Section 1111, in turn, defines murder to include, inter alia, any “unlawful killing of a human being with malice aforethought ... committed in the perpetration of ... [a] robbery.”
At page 9 of his supplemental brief, Lebrón concedes that the success of his challenge to the application of the first degree murder cross reference depends on our finding that the killing of Fontánez did not occur during the carjacking. But the law of this circuit is that “the commission of a carjacking continues at least while the carj acker maintains control over the victim and [his or] her car.” Ramirez-Burgos v. United States, 313 F.3d 23, 30 n. 9 (1st Cir.2002). Obviously, the killing of Fontánez took place prior to the completion of the carjacking under this rule. Accordingly, we reject Lebrón’s assignment of error and affirm the district court’s application of the first degree murder cross reference.
Lebrón also contends that the district court clearly erred, see United States v. Ortiz-Santiago, 211 F.3d 146, 148-49 (1st Cir.2000), in declining to award him a two-level reduction in his base offense level for playing a minor role in the offenses for which he was convicted, see U.S.S.G. § 3B1.2(b). In pressing this claim, Lebrón points to evidence that he refused Evans-Garcia’s directive that he kill Torres, returned Torres’s jewelry to her, and told her to run. Lebrón also contends that he was not the one giving orders or driving the car.
Our review of a district court’s decision not to award a role-in-the-offense reduction is deferential because the decision is extremely fact-sensitive. See Ortiz-Santiago, 211 F.3d at 148. Consequently, “absent a mistake of law, battles over a defendant’s status will almost always be won or lost in the district court.” Id. Here, we see no mistake of law or clear error in the district court’s judgment that, with respect to the offenses of conviction, Lebrón was not a minor participant. There was evidence that Lebrón was the one who proposed the carjacking, secured the revolver used to take the car, held the revolver to Fontánez’s head after possession of the car was wrested from Fontánez, shot Fontánez in the head at pointblank range, and ultimately decided that Torres would be spared. In view of these facts, Lebrón’s assertion of clear error borders on the specious.
Lebrón next asserts, with neither meaningful elaboration nor citation to authority, that the district court erred in counting certain juvenile offenses in his criminal record while calculating his crimi*62nal history category (which was determined to be III). In so doing, Lebrón posits a conflict between U.S.S.G. § 4A1.2(c)(2) (which excepts from the criminal history calculation, inter alia, sentences for juvenile status offenses and truancy) and § 4A1.2(d) (which specifies how certain offenses committed prior to the age of eighteen are to be counted under the guideline for computing the defendant’s criminal history category, U.S.S.G. § 4A1.1). He says that under the rule of lenity, the conflict should be resolved against counting his offenses. This dubious argument is so skeletally sketched that we regard it as waived. See Zannino, 895 F.2d at 17. In any event, because we have affirmed the court’s application of the cross reference for first degree murder and its concomitant establishment of a base offense level of 43, and because we have rejected Lebrón’s only claim of sentencing error that might have reduced his base offense level, Lebrón still would be subject to a life sentence even if his criminal history category were I. Thus, any error in the computation of his criminal history category was harmless. See Williams v. United States, 503 U.S. 193, 201, 203 (1992) (making clear that erroneous sentencing determinations not having an effect on the sentence are harmless errors within the meaning of Fed. R.Crim.P. 52(a)). Finally, Lebrón challenges the district court’s rejection of his motion for reimbursement of court-authorized expert witness expenses in the amount of $388.80 advanced to a defense witness by his trial counsel. The motion was brought under the Criminal Justice Act, 18 U.S.C. § 3006A. The government, citing extra-circuit authority, responds that we lack jurisdiction to review a court’s decision to reject a motion of this sort. Lebrón has not replied to the government’s jurisdictional argument.
We do not address the merits of this dispute. Lebrón’s notice of appeal neither specified the order rejecting his motion for reimbursement nor manifested an intention to challenge it. Accordingly, he may not now contest the propriety of that ruling. E.g., Iacobucci v. Boulter, 193 F.3d 14, 22 (1st Cir.1999); Lehman v. Revolution Portfolio L.L.C., 166 F.3d 389, 395 (1st Cir.1999); cf. Chamorro v. Puerto Rican Cars, Inc., 304 F.3d 1, 3-4 (1st Cir.2002) (permitting an appeal of a judgment even though the notice of appeal specified only the order denying reconsideration of the judgment because the notice manifested appellant’s intention to challenge the underlying judgment). That said, the record reflects that this dispute may be more a matter of miscommunication than substantive disagreement about Lebrón’s counsel’s entitlement to the amount she seeks. If so, we urge the responsible parties to resolve this matter expeditiously.
III. Conclusion
For the ’ reasons set forth above, we affirm the convictions and sentences of José Ramón Caraballo-Gonzalez and Victor Lebrón-Cepeda.