Shadowfang keep incredibly buggy.

[ConnorMagill]

We get to a point where we walk up stairs and it pulls every single mob in the room and makes it impossible to do.

[Aunstic]

If you look at it from the top and remove the stairs leading out from the landing, this pic shows how your group should stay so they don't pull everything in the room:

Keep your distance left-most on the stairs and having no totems up is the way I worked it when I lvl'd.