For me, the most effective use of this kind of thing was a Navy training film I saw when I entered the fleet as an Aviation Machinist Mate.
We were around liquid oxygen a lot (LOX) and it had the potential to be EXTREMELY dangerous because being young men and prone to horseplay, you might be tempted to play around with it.
They showed an excellent training film called LINK TO TRAINING FILM: "The Man from LOX"
The thing that made it so effective, is that it was corny funny, totally sexist, and appealed to every young guy, as we guffawed, laughed and pointed.
But at the very end of the film, in the last minute or so, they show real footage of a guy being wheeled into an emergency room and worked on. His entire torso and face that were visible were horribly burnt, and shown in detail, his eyes open, struggling to breathe. They say he died about a minute after the video was taken.
It was also said that the story was, he was an airman who had been filling LOX tanks for airplanes on a very hot day, and decided to take the venting LOX vapors and filled his coveralls with the cool vapor, then went to have a smoke in his oxygen saturated clothing and burst into flame.
It was a very effective film. In that last minute, and afterwards, you didn't hear anyone laughing or making cracks about the silly training video.
Years later, you could mention that training film to anyone else who had seen it, and their demeanor instantly changes as they remember it.
Very effective. I never saw anyone horsing around with LOX.