Visible crew/equipment: When the crew leave the Red Dwarf game area, a boom mic is visible in the top right hand corner. (00:11:35)
Revealing mistake: During the car chase, the box Rimmer is sitting on keeps moving. (00:21:25)
Continuity mistake: When the crew run down the alley after the chase, the order that they go in changes between Starbug and the hallucination. (00:22:40)
Continuity mistake: When the crew almost kill themselves, Kryten is holding the harpoon gun to his head. The point of the spear is missing but in the next shot it has reappeared. (00:23:30)
Visible crew/equipment: When Holly says she is broadcasting on a higher frequency, when the crew are about to commit suicide, a boom mic can be seen in the top left of the screen. (00:23:30)
Visible crew/equipment: At The End of the episode, when Kryten explains why the Cat would kill himself, a boom mic shadow can be seen moving across his face,. (00:24:55)
Visible crew/equipment: At The End of the episode when Lister makes his speech, the first shot shows a close-up of his face, then it shows a wide shot. A boom mic is pulled out of shot at the top of the screen. (00:25:50)
Factual error: While it is true that lithium carbonate can be used to treat depression and other psychiatric disorders, it cannot be administered in gaseous form. It is a very stable salt and only starts to form vapour at 1,310 degress Celcius. Spraying it about as a 'mood stabliser' at that temperature, as Kryten does, is going to kill everyone on the spot.
Answer: The cello is a large four-stringed instrument, which, when it is played, stands vertically on the floor between the player's legs (assuming they are seated). If it is to grow as large as the other instuments mentioned will, it would require a rather unseemly lack of femininity to be able to encompass it with the legs.
Rooster of Doom