Don't get Jamie wrong - he is still worrying over her. He's just not saying anything about it at the moment, making it a temporary understanding in the 'checking on each others wounds' department. He's about to prompt Kaylee to continue with whatever it was she was going to say when the shell hits and the tank begins to move.

Another shell follows close behind the first, this one with much better targeting. It's the tank's quickness (coupled with the slight head-start) that gets them out of range before they can actually be hit.

It only takes about a minute or so of being jostled around before Jamie decides that buckling himself in is indeed a good plan - and does so with alacrity. "I don't suppose ye got the weapons system up and running on this, did ye?"

He'd feel a lot better about being a passenger if he was able to do something.