There is a possible criminal liability here because many people were killed.
The decision or act of offering so few tickets to so many people can be likened to throwing a small slice of meat to a hungry pack of wolves and this triggered the stampede.
It would seem at this point there was no coordination with police officers in the field.
It's important to have a written contingency plan, so you will know how the police or other agencies will respond in a worst-case scenario.
There was a request for police assistance but it was only that. That was the problem.