[He returns it unthinkingly; it's still a bit of a guarded expression, even like this, but it's genuine. It's open too, at least moreso than it usually is.]

You don't need to thank me just yet. We still haven't worked up to the proper speed, and you haven't taken the lead yet.

[In other words, we're probably going to be here for awhile. Not that he minds at all - quite the opposite, really. He can't dream of letting her go just yet.]