Plot hole: Near the end of the episode Rimmer, Kryten and Lister are all in a Mexican standoff, each facing two shapeshifters who are impersonating them. The trouble is, thanks to Kryten's previous intervention Lister is now a soulless, unfeeling killing machine. Earlier he shot and killed a shapeshifter who could well have been Cat - he didn't know it was a shapeshifter and by his own admission he didn't care. We have already seen how fast on the draw he is - why didn't he just open fire on the six shapeshifters, Kryten and Rimmer in order to ensure his own survival? Don't tell me he was worried about being shot himself - fear is an emotion, too.
Plot hole: At the end, Kryten, Rimmer and Lister are in a lift facing off six gelf shapeshifters, two mimicking Lister, two mimicking Rimmer and two mimicking Krtyen, in a Mexican standoff. Nobody knows who to shoot, as they might shoot the real person instead of the shapeshifter. The problem is that Lister, Rimmer and Kryten are all self aware - they both know they are not shapeshifters. All Lister has to do is shoot the two fake Listers, Rimmer shots the fake Rimmers and Kryten shoots the two fake Krytens, problem solved.PEDAUNT