Shouldn't Harry have fallen to his knees twenty seconds earlier, if he originally heard/saw the explosion via Voldie-simulcast?
What do you mean? He narrated the whole sequence before the explosion, and fell to his knees at the moment Voldemort supposedly died, which is coincident with the explosion. I don't see a problem, let alone one that would be fixed by shifting the narrative back 20 seconds.
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 116.
There is 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.)