Used to teach waterbird at Shearwater Nova Scotia in the 80's. Chucking S61's at the water. Very friendly environment, considering. Of course for real you can forget it. Heavy a/c, sea state 3+, swell running would leave you helpless. But the training instilled confidence. Had a pilot go thru the front screen from the jump seat a few years before I got out there during a cocked up takeoff. They all survived too!!
Footage of a helo landing/taking off from water is enough to put you off flying, though!
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Thermal runaway.