Harry might not be able to transfigure air into solid objects, but he can still transfigure air into other gases, right?
Even if the Death Eaters' masks had some kind of air filter enchantment on them, they likely don't anymore:
We... we were not fighting in them, Master, with you gone... so I did not maintain their enchantments...
So perhaps Harry could partially transfigure the air around the semicircle of Death Eaters into some highly toxic invisible gas while leaving enough normal air between the gas and himself that it would be slow enough to propagate that he would have time to deal with Voldemort and get away and/or diluted enough that it wouldn't incapacitate him?
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 113.
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.)
IMPORTANT -- From the end of chapter 113: