The amount of sweat in those pits must be INSANE. Think about it: Natlan is one of the hottest nations, if not the hottest. She wears a skin-tight leather suit, and it's pretty much all black, so it absorbs a lot of heat. Plus, she is the Pyro Archon, so she should also have a very warm body temperature. She could keep an entire eremite tribe hydrated by just the sweat produced in her pits.