Revealing mistake: When the simulant pulls the knife out of his chest, you can see the knife is a dummy. As the handle is pulled back, the blade does not move at all. (00:25:30)
White Hole - S4-E4
Continuity mistake: When Kryten & Lister are talking to the toaster at the start of the episode, Lister's locks disappear then reappear over his right shoulder. (00:01:55)
White Hole - S4-E4
Continuity mistake: When Kryten tells the toaster not to offer Lister any grilled bread products, Lister is looking down at the table behind him. In the next shot he is looking over his shoulder at the camera. (00:02:50)
White Hole - S4-E4
Continuity mistake: Just after Kryten says what point in time he would like to return to, he is looking down and working with the screwdriver. The camera angle changes and he is looking straight forwards with the screwdriver on its side. (00:05:35)
White Hole - S4-E4
Continuity mistake: When Holly is talking to the toaster and they say about currenty bread, the toaster's handle is half way down. In the next shot it is at the top. (00:08:00)
White Hole - S4-E4
Continuity mistake: When Rimmer asks Kryten if it is the time of year his head goes for retuning, the shadow on his face changes between shots. (00:09:15)
White Hole - S4-E4
Continuity mistake: When the Cat and Lister are trying to cook an egg with a bicycle powered hair drier, you can see the Cat holding a frying pan. When Lister gives up and gets off the bike, Cat picks up a spatula with his other hand and starts poking the egg with it. However, in the next shot, he is shown with both hands on his hips. It's an instant cut with the same conversation continuing, so he didn't have time to put them down. (00:15:25)
White Hole - S4-E4
Continuity mistake: Kryten takes the computer slug out of the machine with his left hand yet in the next shot it is in his right hand. (00:20:00)
Continuity mistake: At the start of the episode when young Rimmer is hanging from the tree, his arms are by his sides. In the next shot his left arm is bent at the elbow. (00:01:00)
Continuity mistake: When Rimmer's mother is talking to him while he is hung upside down, she is stood about a foot away from him in one shot, then in the next she is about three feet away. (00:01:45)
Continuity mistake: When Ace Rimmer is talking to the Cat as a priest, the Cat has the pipe in his mouth in one shot, then he is holding it in front of him in the next. (00:03:45)
Visible crew/equipment: When Ace Rimmer is talking to Mellie, a boom mic can be seen at the top of the screen. (00:04:05)
Continuity mistake: As Ace Rimmer is leaving, the Cat priest has his arms behind his back. In the next shot they are in front of him. (00:06:10)
Continuity mistake: When Rimmer finds the crew sneaking out to go fishing, he is stood facing away from them with his arms folded. In the next shot his arms are behind his back. (00:09:00)
Other mistake: Kryten sees Ace's ship before it materialises. (00:12:55)
Continuity mistake: When Lister drops the magazine in front of Rimmer it lands closed. When Rimmer begins to read it, it is open on the floor. (00:13:25)
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