Hello, Mark ,
My two cents worth.:
Cal probably knew Murdoch from sight. And it might not have been the other way around all that well - Murdoch knowing Cal, that is - maybe just from sight also- and after all Cal was a rich young millionaire playboy - not exactly an inconspicuous passenger ! Lovejoy makes a remark to Cal - something to the effect that Murdoch "seems to be reasonable" - so maybe Lovejoy and Murdoch knew each other more than Cal and Murdoch. "Who knows what evil lurks in the minds of men ?".....or James Cameron.
Hello to you too, Michael -
This, too, may not be the likeliest scenario, but it's just one more to add....again "It's only a movie !" Nevertheless I would have to rate Ewan Stewart ahead of Billy Zane in the acting department. LOL.