血尿

血 = 丶 + 皿 : Mnemonic symbol: blood transfusion.

Xu Xian hurt himself and needs to get a blood transfusion in the elevator's bathroom. He found a petal leaf as donor, which is bleeding droplets into a bowl; Xu Xian gets the blood from the bowl as infusion using some tubes.

尿 = 尸 + 水 : Nefertiti (ni) is drinking from a water fountain (水) in the aorta's bathroom (ao4), but she doesn't notice that at the same time a ghost (尸) is peeing (尿) into the water fountain.