There might not be need for apology, but he'd needed to get that off his chest. It balances.

"That's because you have nerves of steel."

Wry, but not insincere, as he reaches out to accept the joint. Jim might not like battlefields, but he knows he can do more out there in situations like this. In theory, he's probably as good as anyone at simple tasks like tearing fabric into makeshift bandages, turning over cots between patients, keeping track of supplies. Less that he couldn't possibly make himself useful around the medical tents than that he doesn't have the stomach for it. Being better able to take killing a stranger than handling the suffering of a familiar face isn't a positive quality, but it's one he's self-aware about.