Thought I'd post the two typos I found here, since there seems to be no other place aside from fanfic.net (and I don't know if EY is still looking there):

On Asch's Conformity experiment: The correct answer had obviously been C. The other 'subjects', the condeferates, had one after another said that X was the same length as B.

"There was the part of her which said that right was to go on being a heroine, and stay at Hogwarts, she didn't know what was going on but a heroine wouldn't just run away. The voice of every storybook she'd ever read with a hero, child or not, or who didn't run away."

If there's a way to parse that last bit, I can't find it. And with that done, a magnificent chapter, and I'll have trouble going back to my homework now.