Well, Alice has been here for a century and a half. So at least that long.

[They know so much less than what they don't know.]

We're stuck, but people do get sent home. And then sometimes they come back. Also, because I know people here from before or after my point in time and they didn't notice us vanishing for over a year so that's... a pretty good indicator.

[A beat.]

This all makes a lot more sense if you don't think of time as a fixed thing.