maybe they were already dead
Pilot survived the ditching.
Having gone through the helo dunker more times than I care to recall, it is very easy to get disoriented. The key to egress is a hand hold to know where you are. The helo will likely roll, they are top heavy, the engine and transmission are mounted there.
We were trained to wait for motion to stop release your seat belts then egress through the nearest exit. If it was blocked then exit via a crew exit, this was a larger aircraft.
Egressing from this situation with training would be challenging.