He lets the door close behind her, and it doesn't boom shut but just gently clicks, not at all forbidding. "Er. Thank you," he says, a little surprised, and considers advising her to get off the desk, but he quickly realizes that 1) she probably wouldn't, just because he's the one telling her, and 2) it will be much more amusing to let her find out for herself what happens when anyone perches like that on one of his desks.

He sweeps to his own desk and leans against it, arms folded expectantly, and it only takes a few more moments for the desk to rumble ominously, and rattle, and finally start to rise slowly into the air. If she gets high enough, it will tip her right off. He will, of course, step in before that happens.

Really, he will.