I heard from several folks, here and in e-mail or IM, who didn't actually know you could pull off getting the whole Scarlet Cathedral with one pull. Well, yeah. This evening Spiderheart went back with Akaa and two friends of ours with new characters in the upper 20s, and did it repeatedly.
Spiderheart is currently frost-specced, so she has lots of spells to reduce damage, the chance of her being stunned, and like that. I turn on these things while charging straight at Morgaine, then spread plagues in all directions, and just sort of go to town. Akaa, being a holy paladin, keeps Spiderheart healed up and flying right.