I don't accept that Quirrel is necessarily the attacker, but more to the point, I meant that Harry wouldn't know Quirrel would know Hermione wasn't in the hall, so he wouldn't expect Quirrel to behave as if he knew.
Even if Quirrell weren't responsible, he would almost certainly have the presence of mind to quickly check whether any high-value targets (Harry, Hermione, and possibly Neville) were missing. Harry manages to do the same, albeit after some unwarranted delay; he would not expect Quirrell to forget it.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 88-89. The previous thread has passed 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: