必要条件

必 = 丿 + 心 : Mnemonic symbol: 忽必烈 [Hū​bì​liè​], Kublai Khan. Certainly (必) Kublai Khan (必) has to keep face, but he cannot hold it any longer. In the space station's bathroom (Ø4), He absolutely has to (必) tell Brunhilde (bi) his love for her strong character and offers her his heart (心). Brunhilde is a bit embarrassed because all she has to offer in return is a banana (丿). Kublai Khan feels like his heart has been crossed out (the 丿 stroke is crossing out 心 in 必).

要 = 女 + 覀 : Bessie Coleman shows Maud Younger how to use a knuckle duster in the aorta's bathroom. She says it's very important and that Maud will have to get one herself.

条 = 夂 + 朩 : Mnemonic symbol: a bungee cord.

条 = 夂 + 朩 : Mother Teresa helps to clear a sewage pipe just inside the aorta's kitchen. With a bungee cord, she fishes a heap of high heels out of the sewage pipe.

件 = 亻 + 牛 : Joan of Arc and Rosa Luxemburg want to use the anthill's bathroom, but there is a bull blocking the way. He posed them a riddle, and as long as they can't deliver the item or component he asked for to fulfill this quest, he won't let them pass.