The Doctor nodded, impressed. "Make a Time Lord out of you yet, Hiro," he said.

He held out a hand, gesturing for him to do the same. Right there, you can feel how time ripples around us. That means we've moved into a fixed area of time, bit like sticking your hand in gelatin.. Like an incident that can't be changed. Except! We're at Christmas in 2009. Nothing that significant happens."