If James weren't feeling so rotten he would want to tease Sirius about the squeamishness, but this really isn't the time or the place for that. He's trying to look at his arm as little as possible, so he doesn't have to acknowledge how disturbing it is. He doesn't want to look down and see his arm mangled and out of place.

It'll be fine. It'll be fine because they'll find Souji and he'll fix it in less than a minute, and it'll be like it never happened and he'll never have to look at his twisted, limp arm again.

When Sirius first says he should stay behind, his face falls. He opens his mouth like he's about to protest - he can't stay here and let Sirius go off alone to find someone he's never met when that madman could be anywhere. This was different; there was a real danger out there now. But then apparition is brought up, and that sounds just perfect.

"I am. I'm good for that. I mean...just did it five minutes ago, so. Think I'll be alright."

Of course, that was five minutes of blood loss from huge gaping wounds he'd endured since then. Apparition required a lot of focus and he was really starting to feel light headed. He's never apparated under conditions like that before, and it's entirely possible he was only able to apparate before because the situation was so dire. It was either apparate or let the killer put a pickaxe through his skull.

But it has to be alright, because Sirius is not going alone.

"I'm good," he says again, more firmly. "I'll be fine."