If he were to try and explain why he'd done it, he might struggle. Not because he didn't know (he was perfectly clear on that), but because he truly didn't want to. It had simply hurt too much, and he hadn't known how to deal with that. Hadn't known how to talk about it. Hadn't wanted to. So he'd done what was in the end probably completely unsurprising, and failed his friend again. At the time of course it hadn't felt like failing. It had felt good. Better. Admittedly, arguing with someone to that point had been ill advised, but he was hardly known as someone who ever erred on the side of caution. And hitting back had, again, felt good. At the time.
Now, he was here, and he hurt in a different way completely. All the physical pain, from the lesser but still present pain of fresh bruises to the pounding of his head, paled in to comparison to the pain he felt at the disappointment on his friends face. It was no surprise that he'd fallen in to the pattern he had because facing the day after had always been easier by having another drink. Now, though. Now he was faced with Enjolras' glare. And his silence. And that was never a sign of anything good.
He was honestly surprised by the words that he eventually got. He'd mostly stopped where he was because for one he had assumed now that he'd gotten him back Enjolras was just going to storm off in his silent self righteous anger and leave it, and because he honestly wasn't sure where he should go. Where he had the will to go.
But those words, they were so typically Enjolras he couldn't help but hit back, though he didn't raise his voice to meet that of his friends. He sounded almost disinterested by contrast. The effect was added to by the roughness of his voice, coloured by what he'd done to himself. "I suppose you did come to the conclusion that this was entirely about you." He winced internally at the words as soon as he said them, but it was too late to take them back now.