不可或缺

不 = 丆 + 卜 : Bruno Bear (bu) is setting up a wind wheel (丆) with a voodoo staff (卜) in the space station's bathroom (Ø4). He also puts a "forbidden" sign (mnemonic symbol for 不) on it, to make clear that it may not (不) be stopped.

可 = 丁 + 口 : Karl Marx (k) is challenging his abilities (可) in the elevator's living room (e3). He tries to force a nail (丁) into a mandarin (口), just by using his head. On top of that he tries to do so one thousand times, in order to create a bed of nails (mnemonic symbol for 可).

可 = 丁 + 口 : Alternative mnemonic symbol: kebab, from the pronunciation "ke". Karl Marx (k) is preparing a kebab (mnemonic symbol for 可) in the elevator's living room (e3). He also skewers mandarins (口) on the long steel nails (丁) and will only allow (可) his guests to eat the rest of the kebab if they eat their mandarins first.

或 = 一 + 口 + 戈 : In observatory's bathroom, Osvaldo Farrés plays his famous song "Quizás, Quizás, Quizás" (Perhaps, Perhaps, Perhaps) on a flute. Helga Horse listens and doesn't know whether she should maybe give him her mandarin as reward, or perhaps stab him with a spear.

缺 = 夬 + 缶 : Cupid (qu) has almost all pottery pots (缶) of a collection of twelve, but the seventh piece is missing (缺). He asks a crystal ball (夬) I'm front of the elevator (e1): where is the missing piece? The crystal ball replies that he smashed it when he came back totally drunk the night before.