One knock, and Jack's focus undergoes a very brief and inverse nova. He hones in on the sound, then his awareness widens to scope the door, whatever he can hear from the hallway outside...

Well, there were no hoofsteps. That's something, at least.

He takes a moment to steady himself, get himself to a position where he doesn't look quite so much like a wolf backed into the corner of a sheep pen.

Calm. He is calm. He's collected, and controlled, and despite the fact that he's been Jack Harkness for all of one short month now, the title's no more a lie than it' ever been.

"Come in."