That... doesn't really have an answer; the person responsible isn't even aware of it - this space exists separate from wherever she is, and she doesn't seem to know that it's real.

People get brought here for however long, and eventually end up sent home again; from everything I've been able to tell, it doesn't matter how long you're here, you return at the moment you'd vanished from, so generally nobody even seems to realize you were missing.

And, in the meantime, you're stuck dealing with a malleable reality that follows the whims of a bored and oblivious teenage girl, as well as whoever else happens to be stuck here.

[Yes, this is something he's used to going over with people. yes, he has been here for a while.]