[He tenses up a little, the way he usually does when he doesn't know how to feel about close contact. He's not pushing him away which says something in itself, but he doesn't know how to reply to Niko's question. After a few long moments of struggling for words, he comes up with absolutely nothing and instead just sort of touches the hand at his neck.]

I dunno.

[It's said quietly, even for him. And though he does start to relax a little again, he's still not sure what he wants. He doesn't think he wants Niko to pull away, but he should be telling him to forget it.]

What happened to Carla...

[It could happen to Niko, too. He holds onto Niko's hand a little more at that, hating the idea of watching him die, too.]