Corrected entry: In the episode "Polymorph", the 'punchline' at The End of the episode is that the crew of Red Dwarf think they're safe, because they've killed the polymorph creature. But the 'plot twist' is that there was a SECOND polymorph on board Red Dwarf - and the last we see of it is when the Polymorph takes on the appearance of Lister and grins to the camera. But it is never explained what became of this second polymorph. For all we know, it could still be lurking on board.
Corrected entry: Rimmer is seen pressing a button before speaking into a microphone to send out a distress message. But Rimmer is supposed to be a hologram, an intangible being...and as such, can't touch things. HE is not capable of touching things until the Red Dwarf crew meet Legion in Series VI - then Legion upgrades Rimmer with a "Hard-Light" holographic drive, making him a solid being at last.
Corrected entry: Want to know why Rimmer is alive at The End of 'Timeslides'? Here's a theory. Rimmer as a child sees himself from the future visit him to offer advice. He later works out that this was himself from the future. Later in the events of 'Stasis Leak', Rimmer is visited again by his future self. Because of his childhood experience, now Rimmer does not panic but takes his future self's advice and goes into Stasis, therefore surviving the radiation leak.