For those running with a pally tank, pick up a Glyph of Turn Evil for the waves. I did it the first time without but it gets really hairy on waves 8 9 and 10, ESPECIALLY if you get a double mage pull. Generally, I just fear the priest, kill the melee and let groundings take care of the mages until I can get the melee out of the way. If I get 2 mages I just keep a mage feared and then kill the priest... Escaping Arthas is easier than the waves, but overall, it's a great instance.