You can cast instant spells with that one skill though, and sleep is your friend. My tank pet never grabbed aggro on the mobs, so i was running around casting what instant spells i could, and hoped he paused long enough. It's not easy, but it can be done, just get creative with sleep and other tactics. You have to use all the tools they give you, you can't just stand still and nuke away going for leet deeps.