They're lucky that there is a toilet inside the habitat. I heard someone talking (probably on a Joe Rogan podcast) about how when they had to shit, they'd have to go outside to a diving bell which was just a spot to put their head in and breathe (you held your breath to get there from the habitat), pulling down your pants and just freely shit into the ocean. He was talking about how the fish would swarm him to eat his shit, and angel fish could get their mouth right in his butt crack. On his way back in the dark, his flashlight lit up the eye of a Goliath grouper, a fish that could have swallowed him whole if it felt like it.
Yep, I remember that and there is even video (not of the act but of a showing of what they would do without actually taking a dump). The fish learned that when someone went to that spot that they would take a shit and would go eat it.. not only that, you had to swim back through your own shit if it was not... well, you know what I mean.
That doesn't sound like a research facility in the 20th or 21st century, unless it was built and manned by Indians.