After a few centuries, the Doctor's an old pro at not wearing his emotions on his sleeve. His poker face is unshakable, every inch of his outward affect that of someone just passing through. A tourist, maybe, or someone on business, but Rose's barely repressed excitement is infectious; he squeezes her hand. Keep it simple, don't complicate the act too much.

They enter the diner and he immediately picks a booth for them to settle into; it's seemingly at random, but it's picked solely because it's in Jack's section. There's effectively no such thing as coincidence when the Doctor's involved, after all. And then he waits.