I got the strong impression that there was more contrived there (in-universe) than the simple matter of the troll catching Hermione when she was out. The amount of time that passes between Harry injecting her and Dumbledore's arrival doesn't seem to be long enough for the effects of the oxygenation to fail. (Will have to reread / research brain death to be sure I'm not jumping at shadows. It does seem that magic, at least, has concluded for sure that she's dead, and Harry doesn't seem likely to have time to save her even if magic is mistaken and she has a couple more minutes before her brain is irrepairably damaged (the time turner feats would be frankly badass if he could pull it off).) All of which leads me to believe that Quirrel (or whoever was behind it) took measures to make sure that there was no hope of saving her short of phoenix tears, unless they took precautions against even those, somehow.
Easy answer: Dumbledore lied.
Answer which doesn't break established characters: A death eater disguised as Dumbledore lied.
Answer that I can think of that is the least bad: Quiirrelmort steals !Harry's time-turner and comes back from 6PM to spill the soup and provide an alibi for how he suppressed the wards of Hogwarts (which have been established to detect sudden serious injury of a student- that's why Malfoy had to die slowly), and used the troll to kill Hermione for the purpose of turning !Harry into the person who has the motivations required to complete the intended narrative.
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: