It’s difficult to be 100% certain of preventing passengers (or even staff) from having a brain fade moment. I have suffered a few heart stopping moments, thankfully in those cases without any injury to the persons involved, because they completely ignored the safety brief. They were all otherwise seemingly intelligent people but in the heat of the moment they did very silly things.
I won’t go into what the potentially more serious incidents involved but a lesser one involved a certain Lord Mayor, who was specifically briefed not to touch the door handles at any time and to stay strapped in until the rotors stopped, whereupon I would get out and open the doors and let him out. Although he nodded that he understood his brief before takeoff, after landing fifteen minutes later, he instead pulled the door jettison handle as soon as I closed the throttle, pushed the door off its hinges (whereupon it clattered onto the skid and the ground) unstrapped and climbed out with the rotors turning and began putting on his jacket. Then he got into his chauffeur driven limo and went on his way as if it were a completely normal thing to do. I was left to deal with a slightly bent aircraft but at least no-one was injured.
The one highlighted by the OP is a tragic case, I sympathise to all directly involved and to his family.