"I did what I thought was right, looked like an idiot, and got us kicked out of the museum. And got you punched in the face. I told you, I have no idea how to do this dating thing. None at all. It'd be laughable, except it's just pathetic. What does it matter if I'm willing to tell someone that what they said is ignorant and idiotic if it gets someone like you hurt, too? No matter what I do, I can't avoid causing harm."

He knows that he's impulsive, knows that he blurts things out without thinking about the consequences, but that's always been okay before, because it's always been simply himself that he's been endangering. In this case, though, he'd dragged Ned into the middle of something that had gotten him hurt. Doesn't that make him just as bad as anyone else? Worse, maybe, because he hadn't even been thinking about what might happen to Ned when he threw himself into the confrontation headfirst. He hadn't been thinking about anything except his own righteous anger.

"You need ice, too. We both need ice."

And he doesn't possibly feel like he can apologize enough, which is probably evident from the abashed look on his face. He doesn't think that what he said to that guy was wrong, believes his opinion is still the right one, the only one, but he feels now, especially seeing the blood on Ned's hand, that he could have approached it a different way.