I might not have a perfect memory. Basically, presented the attorney's ID to the event desk, got passes to go into the casino, made the guy get out of the way, and then I don't remember any significant cutscene upon entering the casino. I was able to talk to each of the people in the casino, and then went to the backmost area which has a hallway, but there was no trigger to enter a new area. Have not seen the room with a safe.
I may be able to retry the segment from an earlier save and give you some more detailed information, or hopefully get around the problem. Thanks for replying!