Apparently nobody ever taught Jack that it's rude to stare. He watches the whole painful process attentively.

...Sinclair's already refused a med pack, so he doesn't offer one again, but he has to admit he has no idea why all this messing around is necessary when he has one or two still stashed away in his cable-knit sweater of holding.

While he keeps an eye on the other man, Jack takes care of his own injuries with a handy med syringe. You're sure you don't want one? Well, whatever. Jack'll just be over here taking the easy route. The shrapnel cuts and shiny burns on his face smooth away, and a few moments later the pain in his arm subsides. There's a weird popping feeling of something being expelled; he brushes his sleeve, and two crushed bullets rattle to the floor.