This is just i nice trick my and my warlock 2v2 partner found while playing in the Dalaran sewers arena. Since we've done this we are undefeated there.
The trick is to have your lock put down a (Demonic Circle: Summon - Spell - World of Warcraft) at the end of the starting pipe, before you get shot out.
Then try to kite your opponents towards your pipe when they're in range have your lock (Demonic Circle: Teleport - Spell - World of Warcraft).
This will cause you to be in the pipe after the initial wave pushes you out. From there you can either try to keep the opposing team near the pipe and nuke the hell out of them while untouched, or you can wait out the competition if your non-lock partner dies. The only possible weakness is a death knight using death grip.
Simple and effective
I do not know if Blizz meant for locks to able to do this, and as of my current knowledge this is not a repost.
I will post screenies as soon as my Partner gets on.