Thomas's own fangs had retracted. There was literally no point in being ready to fight if he could not make himself do so. If anything, the only thing that might pay off is trying to make it clear that he considered the fight over. Naturally, he picked up on the fact that he was being blamed entirely, but he wasn't going to point that out. As much as he didn't want to be hit by a bus, there were certainly worse things to make a vampire do. Thomas didn't want to convince him to consider those things.

Even if Cooper landed the first blow, and was the one to get Thomas riles up in the first place.

"Actually, I'm a member, too. Just a very new one." So it was understandable that most of the vampires in the nest wouldn't recognize him. "But I'll keep that in mind. I didn't even realize you were a vampire until it was too late to turn back."

He hadn't known for certain until the other vampire had extended his fangs and said he was a vampire. Super strength didn't always equal vampire, after all. Not that he necessarily would have stopped even if he'd had the chance. He'd been far too riled up at that point to want to do anything other than fight.