Stripped away from all other thoughts as a bullet struck his ear, adrenaline pumping, logic and reason gone, fight or flight mode, all his brain could think of in that moment was "fight"
Fight what? The shooter? He's dead? The democrats? Guns? It was meaningless, just a thing to say, and his basest instincts told him "fight" was the thing to reach for.
In the immediate aftermath of violence, all he could think of was more violence.