The Scarlet Monastery instances have been tweaked to reflect the apparent civil war within the Scarlet Crusade. Now there is a Joseph the Crazed handing out kill quests. In the case of Cathedral he is in the middle of the lower level of the pool, battles raging around him, as he dances. Remember that.
Our tank was a feisty, hasty gnome who pulled fast and killed fast, like a dragonfly darting here and there. Woosh woosh woosh. WOOSH! She pulled a path right up the middle of the cathedral. You see? Oh yes, you know where this is going.
Right up the middle, right up to the boss. Yep, those side wings: untouched. So we had friends. Lots of friends.
I ran for it. Being a ghost wolf and much better at sensing imminent death, I survived.
Teleporting back in, I found that the boss and friends had followed me, obviously. And then somehow gotten into a fight with the renegade crusaders. Those NPCs are practically invincible, but also don't hit very hard, so the boss and his friends were all clustered near the entrance.
We whittled down the adds and by the time we got to Mograine he was at about 60%. This may be something for Blizzard to look into fixing, if at some point the fight becomes hard enough that anyone bothers to exploit this for an easy kill. But the result was a strange fight. See, Whitemane still spawned way back at the cathedral, so we all had some running to do to get to her. And then more to get back. So in the end we were fighting the two of them right near the entrance, an epic battle with the leadership of the Scarlet Crusade in entirely the wrong place.
And Joseph danced on.