It seems really unlikely he would do it intentionally, knowing how much trouble he would get into, even if he might not go to jail. However, it seems more likely he was firing “blanks” at people or pointing “unloaded” weapons at them and an “accident” happened.
Only one chamber had a real bullet...the one he fired.
Show us what the difference is between that bullet and a dummy round.
Halls story doesn't make sense. He checked some of the chambers...and doesn't remember if Hanah spun the drum. What did Hanah say?
But he INTENTIONALLY did not check it himself.
It boils down to this: Is Baldwin a psychopath ? A psychopath would do it just to prove to himself he could murder someone in front of the whole world and get away it. It would confirm in his own mind that he was smarter and Superior to everyone.
What might have triggered him is that the main villian in 'Rope' is named Brandon and 'Let's go Brandon' is now a phrase used by his enemies. It would be his own way of laughing in all our faces. The ultimate act in the life of a psychopathic actor.