People have been known to die here, Diana, so do be careful. Granted, they didn't die for long, but it's been known to happen on rare occasions. Usually during the hotel's 'events, however, so you're probably alright indulging your innate curiosity for a while.
Guess what, luv? You've got all the time in the world and even a friendly ghost to help you find a book. Indulge yourself for a change.
There have been many theories floated about this place, including that it's some variety of afterlife. Some of the folks here have been drawn from or around their moment of death and instead of drifting off into the great beyond, they ended up here.
If you want more scientific theories, try talking to Stephen Strange and Tony Stark. They've been experimenting to get people back home. Most of my studies have been about keeping people who want to stay in the hotel (like those who would have no life to go back to) anchored here.