Well, I did have a save prior to the Montelli execution room. Heres why this is important: you have to trigger the execution cut scene. Then (!!!!) Montelli takes the elevator up! You fight him in the room that freezes the game. So, when I did it correctly, instead of the game freezing, I get a cut scene that includes a long conversation with him (see pic below and compare with above). Makes sense now why the game was freezing, the door triggers a conversation with a guy I had already killed twice. 
 
	So, like most early crash/bug/freezes, I hope you have an earlier save. If you don't, I offer this: it is a fun game, and any time you start getting upset, the purpose for which you bought the game isn't being served. Walk away for a bit and come back when some of the fun can be squeezed out. Life is just too short to get angry at the things we cannot change. Peace my friends. I hope this helped.