Emohawk - Polymorph II - S6-E4
Revealing mistake: When the crew get hit by the gas at The End of the episode, you can see that they are slightly moving. (00:27:30)
Rimmerworld - S6-E5
Visible crew/equipment: When Rimmer argues that they should not board the simulant ship, the shot of Lister in the foreground and Rimmer in the background shows a boom mic just above Rimmer's head. (00:04:40)
Rimmerworld - S6-E5
Continuity mistake: During the hold-up scene with the Simulant, in the close-up of her speaking, her face is in darkness. The camera cuts away to Rimmer running for the escape pod, and then back to the Simulant, who is now well lit by a pair of overhead lights. (00:12:10)
Rimmerworld - S6-E5
Continuity mistake: When Kryten, the Cat and Lister teleport when the ship is disintergrating, Lister's locks are over his right shoulder. When they arrive, his locks are behind his back. (00:12:40)
Rimmerworld - S6-E5
Revealing mistake: When the Cat says 'All in all a hundred per cent successful trip' you can see Lister mouth the line. (00:13:45)
Rimmerworld - S6-E5
Revealing mistake: When the Cat says 'Form an orderly queue behind the gunsight' you can see Lister mouth the line. (00:15:40)
Rimmerworld - S6-E5
Visible crew/equipment: When Starbug goes through the wormhole, a boom mic shadow can be seen on the back wall next to Kryten. (00:20:20)
Rimmerworld - S6-E5
Continuity mistake: When the crew walk through the woods, the first shot shows Lister, Kryten and the Cat walking with space between them. In the next shot they are walking shoulder to shoulder. (00:20:45)
Rimmerworld - S6-E5
Visible crew/equipment: When Lister, the Cat and Kryten arrive on Rimmerworld, as the Rimmer guard steps out and says 'silence mutant' a boom mic is visible at the top of the screen. (00:21:05)
Rimmerworld - S6-E5
Revealing mistake: When Rimmer kisses the female Rimmer, the scar on his cheek disappears. (00:22:30)
Rimmerworld - S6-E5
Visible crew/equipment: In the cell, when Rimmer says 'What have I created?' in the next shot a boom mic can be seen at the top of the screen by the window. (00:25:50)
Rimmerworld - S6-E5
Continuity mistake: At The End of the episode, when Lister says, 'I'm saying nothing man, don't want to spoil the surprise,' his hood and locks are arranged completely different than all other shots in the scene. (00:27:20)
Out Of Time - S6-E6
Visible crew/equipment: At the start of the episode when Rimmer says 'any objections?' a boom mic can be seen moving across the top of the screen. (00:01:25)
Out Of Time - S6-E6
Visible crew/equipment: At the start of the episode, just before the Cat says his fridge free diet line, a boom mic shadow can be seen on Kryten's head and shoulder. (00:02:50)
Out Of Time - S6-E6
Visible crew/equipment: When Kryten bends down to pick up the xrays, a boom mic shadow can be seen on the top of his head. (00:05:00)
Out Of Time - S6-E6
Visible crew/equipment: In the medi bay when Kryten says, 'I'll have a talk with him droid to droid,' a boom mic is visible at the top of the screen. (00:05:55)
Out Of Time - S6-E6
Visible crew/equipment: When Kryten walks into the cockpit to offer Lister a beer, a boom mic can be seen at the top of the screen by Kryten's head. (00:10:05)
Out Of Time - S6-E6
Visible crew/equipment: When Starbug hits the unreality bubble that makes the cat invisible, a boom mic can be seen just as the shot changes. (00:10:50)
Out Of Time - S6-E6
Visible crew/equipment: When the Cat becomes visible again after going through an unreality pocket, the shot changes to a wide shot of the crew. A boom mic can be seen to be pulled out of shot at the top of the screen by Kryten's head. (00:11:40)
Out Of Time - S6-E6
Revealing mistake: When the crew go through the unreality pocket that makes Starbug disappear around them, part of the Cat's face disappears into the background. (00:12:05)
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