Agreed. Especially if we judge the story by usual storytelling standards. Though that's harder to do after HPMoR itself has been teaching us the difference between story-logic and what is realistically probable, and mocking stories in general and the original Harry Potter in particular at every turn for that stuff.

I don't think that hole was even necessary. Voldemort did need to let Harry keep his wand for the Unbreakable Vow. and could have intended to have someone disarm him afterwards. So just have Harry prepare the antimatter bomb while Voldemort is dictacting the Vow, and announce it before he could be disarmed. What do you think?

(Sure, that would probably mean no "final exam" for the readers. Now I hated the idea of holding the story hostage, and refused to even "try to try" for that reason, so that doesn't bother me. I suspect I'm in the minority about that, though.)