The bathroom was ordinary, indistinguishable from any other.
In the cognition of Kuwei, there naturally was no concept of a bathroom; Misty City people didn't need to bathe or had much need to excrete. The act closest to bathing was probably to wander in areas where the mist was thinner, and every lifeform of mist they swallowed became part of their bodies—excretion was simply wasteful.
But in the exploration of the Foreign Domain, Kuwei did witness some civilizations' pretense; in most human civilizations, cleaning the body was an important part, their frail bodies couldn't even bear the cover of dust.
If it were just for the sake of survival needs that they cleaned themselves, the Misty City people would simply laugh at the frailty of humans. But some humans actually took joy in cleansing their bodies, even when already exceedingly clean, they still washed themselves and expended a great deal of time on such behavior.
Illogical.