And we are back to cold water shock.
Immersion suits and air bottles (STASS or equivalent) would at least have given them a fighting chance.
Even being shown a video of how to escape underwater would have better than nothing.
Planned flight over water out of auto range of land with water temp less than 5 degrees.........
I assume the pilot didn't have an immersion suit or air bottle.
Being able to get loose from the helicopter would have given the passengers a fighting chance. That and possibly a flotation device probably would have been enough - with the doors open, getting out wouldn't have been an issue and apparently the pilot was picked up fairly quickly. They would have been cold and wet, but....