悶聲悶氣

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.

Mnemonic symbol: a balloon. The Queen of Hearts is disappointed by her balloons. She expected them to float upwards, but in the space station's bathroom, They float randomly in all directions.