闷声不响

闷 = 心 + 门 : Mahatma Gandhi (m) lost his heart (心) when he accidentally dropped it through a trap door (门) in the floor of the encampment ((e)n4). As soon as the heart fell through, the door closed very tightly (闷) which makes Mahatma Gandhi quite depressed (闷).

声 = 士 + 尸 + 丨 : Sherlock Holmes (sh) hears the terrifying sound (声) of bone (丨) on stone in front of the engine ((e)ng1), and he's sure that there must be a ghost (尸). Indeed it's only the bachelor (士) who wants to scare Sherlock.

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.

响 = 口 + 向 : Inside of the anglepod (ang3), Marie Curie (xi) makes loud noises (响) clashing together a mandarin (口) and a sky fruit (向).