Warlock from vodka Qtica killed all 4 a few days ago so not sure if this is a world first but congrats. To those saying you have to challenge yourself, it is more like "you need to gear the hell out of yourself" to win. Having beaten Millhouse Disruptron with 95k dps I am happy I was able to do the same as a warlock from vodka :3
Maybe some of you are seeing it/doing it with low gear and if you are PLEASE post a video rather than posting your claims. However when I am watching the members from vodka they are decked out in heroic sha-touched weapons, trinkets, 4 set bonus and what not and only Qtica the warlock has beaten all 4 from what I have seen. So it really seems to be a HUGE gear check more than anything else. That or just playing a godlike OP class with gear