It’s probably safe to say that Evrina hasn’t encountered someone with as strong a will as hers in a while. Alex has let several mean spirited things slide across her with little more than a grimace, and the rest of the group has basically been stunned into silence. In this situation Reggie is that most dangerous of creatures, the one with nothing to lose. Additionally he’s the kind of person who would want to bring down horrible retribution on anyone who doesn’t get the job done. He’s only going to turn the other cheek as much as it takes to increase the force of his counterattack. In that moment he relishes the brutality of the action. Feels the thrill of hurting someone else as much, or more than, they hurt you. It can be a very intoxicating feeling. The bully’s high, if you will.
All of this, when looked at from a distance, illustrates the fog that exists in most situations. Someone is bullied and they lash out. Sometimes against the aggressor, sometimes against an easier target. The feeling of weakness and helplessness spurs them on. Virtually every person will play both parts at least once in their lives.