So, animal control came and took the creature away. Turns out there's this little crack in between the wall and the sink. It's likely that the bat flew into the building from the top floor and made its way down through the wall and into our bathroom.
The lady said we were fine to keep using all the stuff in the bathroom since we hadn't touched the bat, and they called two days later to say the animal didn't have rabies. Really?! You waited two days to tell us that while we were using stuff touched by the bat?! (Actually, I didn't have anything it that cabinet...so really it was only my roommate who might have gotten some disease...)
We boarded the hole up with cardboard.