The photo says…”Miami Dade police surround the plane”. What for? Were there donuts aboard? Guy opened the door, fell out.
Even if he managed to get the door opened against the slipstream, there is no way on earth that he "fell" out of the plane. Try it sometime.
I want to modify my position in this. I have been assuming that this guy was sitting next to the pilot.
if he was way in the back of the cabin, and out of his seat, he could access a door that opens upward - easier to open in flight than a front-hinged door. And if the guy were foolhardy enough to open the door, it is possible that he could “fall” out. The set of circumstances that could lead to such an outcome are improbable in the extreme - so extreme that I still think this had to be an intentional act.