The mechanisms for ants and humans clumping behaviours are, I expect, quite different. My understanding is that we are looking and listening while ants are smelling and feeling. This means that the actual architectural insights you get from ants - put a column here and a door there - might not generalize to humans.
In very crowded situations you end up with something closer to the ant-like behavior. Your visibility is reduced to your immediate neighbors, and theirs is similarly limited. This prevents the deliberate movement you'd see in lower crowd situations, or where people are very familiar with their surroundings.
That is, a stadium exit is not like the exit of a thousand workers from a factory at the end of the shift. The factory workers (ok, not always) know their path and may have an action to perform on exit (punching out) which establishes a tempo. A stadium exit is more freeform and people are less familiar with their overall exit plan. So they jump into the stream and go where it goes. They have to move as fast as the crowd behind them pushes them or faster.
Stadiums have signs though? Clearly lit pathways, signs, and directions to all the exits. I'm pretty sure it's the law to have those (at least for fire codes). I would be highly surprised if people followed their nearest neighbor instead of moving in a direction denoted by the signs and pathways prescribed.
I visited Venkateswara Temple in India, which gets some 50~100k visitors daily. The main takeaway I got was that it doesn't really matter what the path is -- you don't get a say in the matter. The flow of the crowd moves you along, and that's all there is to it.
You have people pushing from all around you (in a vague general direction), and next to no space to actually influence your movement -- and the lack of choice in the matter is fairly incredible. The pushing stops coming from any particular place, it just becomes some indeterminate feeling of pressure forcing you along.
I'm quite positive you could easily be crushed by it, getting caught between a pole somewhere in the path, and with no external factor to influence the crowd (a wall is clearly visible, a pole is not), simply be pressed against it indefinitely.
A stadium probably isn't an intense, but likely similar -- once you're in the stream, the only thing that matters is stream.
Eventually, you're suddenly ejected from the stream and have to figure things out for yourself again.
> the lack of choice in the matter is fairly incredible. The pushing stops coming from any particular place, it just becomes some indeterminate feeling of pressure forcing you along.
You can experience this in total safety any day you want by riding a subway during rush hour in a populous city.
Yes, but when you're in a packed crowd even these may become difficult to see for any individual. Think no real room to move freely, maybe not even 1' in any direction other than "forward", the direction in which the crowd is clearing. Some people see them, hopefully, and those are the ones that determine the direction of the crowd's flow. Which may be towards a specific exit and not to all exits.
