He just froze at Logan's words, blinking in confusion. He hadn't killed anyone? Karr was alive? The revelation caused a wave of relief so profound through him that it was a good thing he was already crouched, because his knees might have buckled. The subsequent insult was lost on him. Well, up until Logan accused him of leaving Karr to die. It was true enough, but Nik had thought the kid was indeed dead. The man was actually relaxing a bit, letting the knowledge that he'd never killed anyone sink in. So much so that he didn't catch the change in Logan's behavior until it was too late.
The attack from the older man was the perhaps the last thing he had expected, though the sound of the claws coming out was definitely one that brought his hackles up. Not even thinking about it, the crouch shifted as Logan came at him. Really, him trying to fight someone with Wolverine's level of training was laughable. The first blow of the fists drew a roar of rage and pain from the creature, though, and his response was to try and grab the other man and sling him away. Very far away, as far as he could manage. He didn't know enough about Logan to realize that such a measure was incredibly ineffective. No matter if they hit a tree or not.