Mmm, yeah, basically - as long as they want to. Turned out humans don't love the idea of being somewhere eternally, though, so we made a doorway out. No clue where it goes - they might merge with the universe, or something?

[It's an afterlife for dead people!]

There actually haven't been all that many people to take it, yet. I think maybe they just wanted the option. Makes it feel a little less claustrophobic. Not that it's small, but you know, eternity's a long time.