Not just one, but both of Garrot's eyebrows raise up. Ten is special and... has emotions?

"So, what makes you special? Is it that you get bored?" Garrot thinks that's pretty special. "If anyone was special, I figured it'd be Twelve since they're the strongest."

Dressed like a kid, playing with a kid's toy, maybe Ten'll gossip like a kid? The doctor sees the chance to gain an advantage, so he's jumping on it.