Impossible scene (Kurt Russell's last scene) SPOILERS

When he kicks the bucket and THEN reverts the propeller.

Don’t take it the wrong way, the drowning sure was more realistic than the one in The Abyss.

HOWEVER, two problems I noticed:
While he sure panics on queue, he seems to convulse and stop moving BEFORE taking in the water (you can even hear it when he takes it in). My diving experience tells me that it’s the other way around: when you cannot keep yourself from inhaling the water anymore, THAT is when you start convulsing for real (hardwired reflex), not before.

Once that happens, you’re a goner. However here Kurt can be seen somehow still commanding enough control/life to push the button AFTER he’s done convulsing (meaning after his brain dies or at least suffocates). Unless it’s meant to be a Moby Dick kind of action (Ahab waving his crew to follow him even though he’s clearly dead at this point), seems absurd.

Anyone who has actually drowned and survived, does it always happen like that? I ask because I once almost drowned when playing who could swim the farthest underwater in the pool (shallow water blackout) yet didn’t convulse or anything like that. I would assume that Russell or anyone in such situation, if they hyperventilated enough before going in and somehow avoided panicking, could have at least a good change of inducing such blackout and spare themselves an awful death.