Some of you people are killing me. Look at the water temp, and the untrained pax.
I was fortunate to be the beneficiary of both helo dunker/escape training, and the hypothermia/cold water training in the Navy. Even with that training, without a well crafted anti exposure suit, I'd have as good a chance as any of them of being dead with immersion as a passenger with little to no CRM in the event of a quick loss of power/ditching into 4 degrees C water.
FFS, I am pleased that anyone at all is alive after this unexpected ditching.
Why did the engine die? That's the question.