I'm one of the few who has yet to see the movie Titanic from start to finish. Why not? One of the clips I saw before it opened struck me as a scene so far-fetched and implausible, I was afraid I'd sit there scowling.
Which scene? The bit of the mother reading to her two kids as the water's rising.
Now, granted I am no expert in human behavior, but I could only envision a different reality -- when the fight/flight response kicked in. And it wasn't a bittersweet vision of a mother and her two kids having any kind of peaceful death.
My dad, who rarely goes to the movies, did see Titanic. He served in the Royal Canadian Navy during World War II. He knows from the North Atlantic and its water.
His response: that water would be so cold, there's no way anybody would be rushing around in it. And they had leather-soled shoes, which would be so slippery, they'd be falling all over the place.
In other words, it wasn't only those who actually fell into the ocean who'd have frozen to death in that cold, cold water. Between falling and frozen feet, many wouldn't even have been able to make it to the stairs.
That would have meant a lot less drama in terms of the film, though. How many narrow escapes did Jack and Rose have as the water was pouring in? More than one. In reality? They probably wouldn't have been able to get very far at all.
This dance between reality and drama is something that historical fiction writers have to wrestle with all the time. Facts will get altered or changed for the sake of drama. How much is too much?
As long as it's clearly labeled "fiction," I think that's up to the author. But it is a decision we face, and one that isn't always easy.