I wish the 1997 film was more historicaly accurate. But, the sets were near perfect in all cases. Except when Andrews gives Rose directions to find Jack. I looked at the blueprints and this crewmans passage did not exist.
I cant picture Murdoch shooting passengers. He probobly felt bad enough for being responsible for the collision. I think it is possible he shot himself. The only other candidate I can think of is Smith.