Rory peers into the room behind the Doctor, and he frowns. Even if there are the parts and bolts of some mysterious contraption on the floor, it's entirely too empty and clean and far too quiet for a man who's supposed to have all of space and time at his fingertips. There's no reason for the Doctor to come back here of all places. Something is definitely wrong. He meets Amy's glance and understands almost instantly that she's asking for back-up.

"You left without saying anything," he begins cautiously. "We thought you might be...sick or something."

It's a flimsy lie, but the Ponds are both concerned and the Doctor isn't likely to tell them what's really up without a bit of coaxing.