He laughs.

[Okay, then yes, you do.]

And he flies out of the house, un-invisibles, walks back up to the door, and sticks his head through it.

"Why's the door open?"

"Aren't you halfway across the country or something?" inquires Hilary.

He laughs, gesturing down at himself to indicate his obvious presence. "Do I have to answer that?"

"Yes."

"Got bored, came back. Why's the door open?"

"Because I felt like it. And if you're so bored, you can help me bake cookies."