百思不解

百 = 一 + 白 : Mnemonic symbol: a one hundred 元 bill.

Beelzebub (b) enjoys preparing to allure mortals. In the airplane's living room (ai3) he's waving a flute (一) as a magic wand and enchanting one hundred white flags (白) to look like one hundred (百) one hundred 元 bills (百).

思 = 心 + 田 : Socrates is feeling blue in front of the space station. He's thinking of burying his heart under a field. When he finishes, he realizes that he has created some kind of small planet, with his heart at the center.

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.

解 = 刀 + 牛 + 角 : Mnemonic symbol: acetone, in which anything can be dissolved.

Inside of the elevator (e3) Joan of Arc (ji) is dissolving a horn (角). A moment ago she cut the horn from the bull's (牛) head using a cleaver (刀). The bull is still shocked as he sees Joan of Arc dissolve (解) his horn in acetone (解).