Eerie foreshadowing...
Film is an odd medium...
This is repeated in numerous Natalie Wood films, including the doomed-laden, suicidal swimming scene in SPLENCDOR IN THE GRASS (and "drowning" in the bathtub!), and the piece of wood (literally, wood) with her character's name carved in it by the beach in GHOST AND MRS MUIR, like a seaside tombstone. And there's another one when she's tiny and crossing a rushing river and Wood almost got swept away for real (I forget the title).
When young Natalie Wood was leaning over the side of the boat in THE STAR and Bette Davis warns her to be careful not to fall over. And then Jim replies "Don't worry, she's a natural sailor."
And then there's that moment after Corey Allen;s car goes over the cliff and into the ocean in REBEL WITHOUT A CAUSE and Wood hesitates like she might jump after him.
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LBJ's mistress on JFK:
https://www.youtube.com/watch?v=WcXeutDmuRA