肿

肿 = 中 + 月 : The moon (月) and Julian Giant Squid (zhu) are playing darts inside of the engine ((e)ng3). Right in his first turn Julian Giant Squid doesn't hit the dart board (中), but instead hits the moon's eye which starts swelling (肿) and develops into a tumor (肿).

中 = 丨 + 口 : Mnemonic symbol: a dart board, because you always try to hit the center.

Julian Giant Squid (zhu-) is throwing dinosaur bones (丨) as darts on a dart board in front of the engine ((e)ng1). To make it a bit more difficult he's throwing mandarins (口) into the air as well and skewers them up right in the center (中 is a mandarin skewered on a dinosaur bone) in mid flight with the dinosaur bones. He's still able to consistently hit the center (中) of the dart board.

月 = ⺆ + 二 : Yu the Great (yu) is modelling a moon (月) in the elevator's bathroom (e4). He uses a stapler (⺆) to staple a lot of capacitors (二) together to form a moon shape, while the real moon is sitting for him.