As affliction warlock, put up dark soul dots on all targets and leave arena. Your dot's left on the target will now completely ignore resilience, provided that your partner is still in the game. The dot's should almost instantly kill the opposing team if you applied them with trinket/procs, unless they are obviously smart and use some form of immunity.
Drawback: the player who left arena won't gain mmr/points. But the people who remained in arena will get points/mmr increase. Don't have to explain how it can effect your teams mmr, etc.
Same works for other classes as well of course, including bleeds.