Billions would be a bit difficult to wrap his mind around, true, but thousands he could do - and for a moment he wound up staring at this new, strange version of the Doctor. Had it really been that long? And then the rest of it sunk in. After years of thinking he'd never see Scotland again, the Doctor's people had sent him back - and they'd sent Zoe home, too, apparently, and separated them from the Doctor in the process. Only- that hadn't happened for him, and after a moment, he shook his head quite emphatically.

"You mean they sent us home? But- Doctor, that never happened. The last thing I remember before coming here was being stuck behind one of those forcefield things of theirs because they wouldn't let Zoe or I see you, and that was when we were on your planet. I never went back to Scotland. I wound up here instead. How could that be?"