A transfigured port key in his glasses does seem possible, or some kind of explosive device hidden in the transfigured ring.
EDIT: Fawkes is also a way out here, if Harry can delay an enemy attack for several seconds
Second edit (the serious one): The ring contains some kind of binding device. This could be the blinding potion Harry used in battles, a set of flash-bang grenades, or (most likely) a seventh-year variant of the blinding potion Harry bought off a student. This countermeasure will blind the unwarded death eaters which allows Harry to immediately fall to the ground and call Fawkes. Fawkes teleports Harry out and allows escape.
I was wondering how much retroactive power we would have.
Harry would know, or be able to look up, any number of chemicals that would react very poorly to the open air. It would be exceedingly foolish to carry one on his person, transfigured, such that he would simply have to negate the tranfiguration to have a distraction or attack, but would such a thing be in our power to suggest into existence, if we thought of a sufficiently non-foolish way for Harry to carry this?
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: