Continuity mistake: When the simulant drinks his drink, he lifts the cup up to drink, yet in the next shot he lifts the cup up again, repeating the same action twice between shots. (00:13:50)
Revealing mistake: When the simulant hits Able over the head with the steel bar, you can clearly see it bend. He hits him a second time a few moments later and it is straight again. (00:14:45)
Continuity mistake: When Able screws Kryten's head on, he is standing in front of him. In the next shot, Able is behind Kryten next to the table. (00:15:30)
Revealing mistake: When Able screws on Kryten's head he only turns it once, yet in Tikka To Ride, Lister screws his head on at least twice around. (00:15:30)
Continuity mistake: When Able takes his head off and throws it at the simulant, he throws it forwards towards where Lister is standing. The head manages instead, somehow, to hit the simulant standing next to the gelf on Able's left. (00:20:00)
Revealing mistake: When Lister kicks the simulant in the head, you can see he misses him by about a foot. (00:20:00)
Continuity mistake: Able's head bounces off the simulant and lands behind him, yet when Lister sends the gelf and simulant back to their ship, the head is next to him on the floor. (00:20:10)
Continuity mistake: After the Cat says about mooning out of the windows when Starbug gets hit, Kochanski falls back on her chair with her arms outstretched. In the next shot she is holding onto the monitor again. (00:25:00)
Continuity mistake: When Lister punches up the Leviathan's destination, it reads 'Theta 4'. However, in the next scene in Starbug's medibay, Lister says that the Leviathan was headed to Delta 7. (00:23:10 - 00:24:25)
Factual error: When Kryten revives Lister with the defibrillator paddles, he places them on the clothing he is wearing. Defibrillator paddles need to be applied to bare skin for the electricity to get through. (00:27:35)
Continuity mistake: A door has appeared in the main living area of Starbug that was not there in previous episodes. (00:01:50)
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