I can only think of one thing that can cause this problem, because I had it too (avoided it by killing van der Graaf and any witnesses), but have you modified anything in APEngine.ini lately? Sounds like a sound file is not being played for some reason, and I've had a LOT of endgame crashes thanks to sound files (dialogue lines not playing, some sounds completely crashing the game).It worked 100% when I reset everything related to the mouse and "jerkiness" fix back to the default optionsjust hap, so I wasn't in the mood to investigate further, just happy I could finish the game. Try re-editing your .inis to see if it does the trick. Or you could always shoot them in the head. No hard feelings. You even get a perk and a mass murderer story on the news, and they blame it on terrorists. Har har.