'Nothin' that's anythin' t'do with you,' he returns, watching the tobacco get spooned out. It smells lovely, but he's hardly going to point that out.

And the brusque reply is just a matter of course, really. He doesn't tend to share his private stuff, and just assumes Kate would feel the same way, given...well, everything.

And he's always been a bit rubbish at being undercover. It just doesn't sit naturally with him, deception.