If you're worried about time, there's no need. It doesn't pass while we're here. [Which is weird but OKAY.]

[At any rate, despite the mildly unnerving look you might catch toward the rabbit (WAIT UNTIL IT IS COOKED-), he nods.] I mean exactly what it sounds like. You think about what you want to see behind the door in terms of scenery, furniture or whatever... And it'll show up.

...Doesn't work for getting people though, so don't try that.