Jamie doesn't understand everything that Billy says - he looks awfully confused, for instance, when Billy mentions 'genius programs'. But there are some aspects to it that he does get all too well, and there's a moment when he is looking at Billy with a very thoughtful expression.

"That's what it is." There's something about Billy that's reminded him of something, but he hasn't been able to put his finger on it until now. It's that curiosity, that urge to learn things...and that ability to create. "Ye remind me a wee bit of the Doctor."

There's large differences between the two, and Jamie's not under any delusions that there's not. Still - he means it to be a good thing. He thinks rather highly of the Doctor, after all.

Seeing that haunted expression, though, he adds, "I hope ye don't mind my thinking so." He's not sure if it would bother Billy or not.