The Doctor turns back to Hiro, raising an eyebrow in surprise. "That's...really impressive," he says. "I've met quite a few human time travelers, but none with your aptitude." There's more concern in his voice than just pride. That sort of aptitude could be abused if someone got their claws into him.

"No," the Doctor said. "It's actually cold. Like a block of time-frozen ice. The time in the air around it is compensating, trying to actualize the time differentials."