"Careful, I might start thinking you're worried about me." He says it with a teasing lilt up at her, lips pulling into an amused smirk at her pragmatism. He doesn't have the luxury of worrying about tonight — if it goes wrong then he dies, and frankly Eames isn't about to let that happen — he has to be confident, ready. Pulse steady and breathing even while he tries to keep their plans fresh in his mind, even with the pain.

So the smirk and the easy humour are there to punctuate his confidence that things'll go at least mostly to plan.