Thanks for getting back to me. I went through the convenience store and picked up the shotgun, went further through the passageways, used the lock mechanism and picked up the artifact, and then walked along the dock and exited through the door that's right by the car. Both times the game crashed just as I was walking through that door. However, yesterday I had another crash in the waterfront area in front of the nightclub, after having already visited a couple other areas in the game, so maybe the item order and specific doorway aren't the issue?