Your phrase remind me of Emine's song, love the way you lie, that has the phrase "maybe that is what happens when a tornado meets a volcano".
I think it is extremely clear it is not he has no emotion, more like he is emotionally dull after getting strike so hard after losing Summer. That is why I think Bella is so important for the novel, even for those that prefer other girls. I put it like this in another post
I still was not able to see how other routes develop, as I cannot avoid every time I repeat the game going for Bella. But at least in the scene in the locker, you see him react to her. His whole "ohh fuck, don't tell me I am falling for this bitch" line of though was perfect. Finally he feels something and is for one selfish, totally broken and potentially dangerous, irresistible and breathtaking girl you cannot help falling for.. sorry, I think my feelings were mixed there. But you get what I mean.