Crowd density is certainly the key here. Over a certain density crowds move like a liquid. Under a certain density crowds get much more difficult to model.
This is not new in any way, btw. This paper seems to specifically address the running of the bulls.
This is not new in any way, btw. This paper seems to specifically address the running of the bulls.
https://www.science.org/doi/10.1126/science.aat9891