Quirrell said he considered killing Harry at some point, so there are 3 possibilities: 1) he's lying, 2) there is a dark binding ritual that he doesn't know about, or 3) there is no dark ritual. Considering his knowledge of dark rituals we can rule out number 2, and since there isn't a clear reason why he'd tell this specific lie, I'm going to go with 3.
If Quirrell doesn't want Harry dead then obviously he'd stop the Centaur, and if he does want Harry dead, he wants to do it on his own terms, with nothing left to chance and no loose ends, so again he'd stop the Centaur.
Or 4) He considered it, and discarded it because of a dark binding ritual.
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 99, 100, and 101. The previous thread is at nearly 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, 19, 20, 21, 22, 23, 24, 25, 26, 27
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: