Bones takes a glass. Jim pauses in the act of reaching for his own. They're trying to find some element of normalcy, but when Bones says that, everything that's potentially normal goes tits up and Jim starts to realize just how wrong this situation is.

That's not a bullshit response.

The reason for being unfit, before? That was bullshit. Being unfit is not.

Jim mms as a response, and makes himself pick up his own glass and take a sip. He may still shout at the other man, depending on just how this goes, but he'll give him a moment's grace.

Or a moment of horrible anticipation, he supposes.

Eventually: "Why?"