Easter egg: On disc 3 on the main menu screen, if you highlight and press the red 'JMC AMMO' button, this will show you picking up a bazookoid. Before firing the bazookoid, push one of the arrow keys. This will cause a light closer to the right side of the screen to light up. If you press enter, it will blast the code panel on the door. You are then taken to see a very funny Red Dwarf Trailer.
Easter egg: On disc 3 on the main menu screen if you highlight and press the red 'JMC AMMO' button this will show you picking up a bazookoid, if you fire and blast the code panel on the door you are then taken to see Chloe Annett's audition for Kochanski.
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