[Update: and now there's a fifth discussion thread, which you should probably use in preference to this one. Later update: and a sixth -- in the discussion section, which is where these threads are living for now on. Also: tag for HP threads in the main section, and tag for HP threads in the discussion section.]
The third discussion thread is above 500 comments now, just like the others, so it's time for a new one. Predecessors: one, two, three. For anyone who's been on Mars and doesn't know what this is about: it's Eliezer's remarkable Harry Potter fanfic.
Spoiler warning and helpful suggestion (copied from those in the earlier threads):
Spoiler Warning: this thread contains unrot13'd spoilers for Harry Potter and the Methods of Rationality up to the current chapter and for the original Harry Potter series. Please continue to use rot13 for spoilers to other works of fiction, or if you have insider knowledge of future chapters of Harry Potter and the Methods of Rationality.
A suggestion: mention at the top of your comment which chapter you're commenting on, or what chapter you're up to, so that people can understand the context of your comment even after more chapters have been posted. This can also help people avoid reading spoilers for a new chapter before they realize that there is a new chapter.
...and if I replace my previous assumption that Quirrell collapsed as a direct result of Dementor influence that was opened by disappearance of Potter's Patronus, with the much more plausible assumption that he collapsed because of magic incompatibility with Potter's Patronus of the same nature as what killed him the first time, and only additionally suffered from Dementors, then it doesn't follow that Dementors cause overwhelming harm, and so that prolonged exposure leads to death. This also explains throwing away the wand: make own magic weaker to reduce the effect of magical incompatibility.
Thus, now the hypothesis that Quirrell died seems less plausible than the alternative.