The kill switch has been thrown in this animal now. Maybe the first one was "play". Maybe the second time it was play or whatever when the guy snuck into the tank after hours. But this time, the animal has has associated humans with being prey. Not as food, which is why he hasn't tried to eat them (yet). But just as something to kill.
There is nothing that is the human equivalent of the overwhelming killing instinct that predatory animals have in humans because our actions are dominated by our frontal lobes with the notable exception that it has been proven (through neurologic examination, neurocognitive evaluations and imaging in FMRI) the brains of certain types of criminals (i.e., serial killers) are measurably different than those of "regular people."
This fish obviously isn't feeling his surroundings so the best thing to do is let him. I don't buy into this idea that he can't survive in the wild. After ghosting 3 people, he has some serious ocean "cred". Home slice could roll up on any pod he want and own it. He'd be gettin all the females.