Finally got the nerve to try it again after a 'lil bit better gear. Had a wipe which I nearly couldn't recover from (shammies kept getting in combat trying to rez) while still at the 'scourge wave' part. Had another 2 deaths (tank and resto) during the fire phase, luckily Arthas had enough hpz to let me get out of combat to rez them. The bosses were actually a joke compared to other bosses I've cleared.

My only question is...How in the world did Hachoo do the timed achievement?? My girls had to drink about every 3rd wave.