Yeah this happens to me in arena. Once in breakout I got betrayed for a BR. I wan't going to let him get away with that, so I betrayed him next round before he could kill me again. He got mad and he tried o betray me the round after that, but he missed some of his shots and shot his other teamates, so from then on it was full-on warfare between our team.
I had a similar thing last season but I think the guy was just killing teammates to troll us as he'd open up right out of the gate. The first round he took me and another teammate out in the first 10 sec. The second round I jumped around and avoided him, but he still tried to kill me and got another teammate. So after evading him for two rounds, I decided to get rid of the problem. As soon as the match began I Spartan charged him. We went on to win that round and then when he opened fire again the next round I clubbed him and we won the game. I hate getting down on their level more than I hate getting betrayed, but sometimes you gotta take one for the team.
I think Breakout just needs a rev'ing up of penalties for quitting and obviously intentional betrayals/and trolling.