[rob74]

More concretely, the warning that took precedence was the GPWS telling them to PULL UP. If this didn't convince the captain that flying towards the sea was a bad idea and he should in fact pull up, I'm not sure any other technical measures would have?

[bjornsing]

The mechanical force from the other pilot pulling up (as if his life depended on it) might very well have “convinced” him.