The heads of the people stuck inside one open doorway is what I saw, that I spoke to. Did some one outside open up that door, after a pile of people had been pressed against it? Are you sure we are talking of the same doorway? How would you be sure?
In any case I was caught in two crowd panic situations, and managed to save one girl from being crushed, by bracing my legs against the walk to protect her. Legs rated at that time for 3/4 of a ton pressing force.
The video we saw was shot by a person in the audience maybe 20’from the stage. It shows the pyro start going off and lighting off the foam they were using for sound insulation on the stage.
It takes the audience several moments to realize the situation. The flame spread was fast, intense and smokey. People start for the doors they came in and pass other doors on the way. Quite a few were locked and people piled up there.
The person who shot the video gets out into the parking lot and then goes back to doors and captures many peoples last moments.
I doubt the video is in public domain.