Managing to get back aboard, the others find that a third Psiren has disguised itself as Lister, leaving them unable to determine who is the real one and forced to hold both at gunpoint. To determine which one is false, the crew ask them to play guitar, and shoot the fake when it plays well, knowing the real Lister is terrible despite his belief that he is excellent, determining the Psiren's illusion was based on this belief that his genuine skill set.
After regaining access, the crew finds a third Psiren posing as Lister, creating confusion and forcing them to hold both suspects at gunpoint. To identify the impostor, they devise a guitar test, aiming to eliminate the fake by shooting it when it plays well. This strategy exploits the imposter's false belief that Lister is musically skilled, which is not true.