Large crowds can be very dangerous, especially when there's a panic of some kind. Look up something as old as the Triangle Shirtwaist factory fire, more recent night club fires, the Who 1979 concert disaster, the many soccer game crushings/tramplings.
There was also the 2014 Shanghai stampede, where folks on a confined platform panicked for some reason. Some 36 people died, another 50 were hospitalized, and many more were psychologically traumatized. In the case of the above fires, it isn't just fire that kills. People who can't escape quickly panic and trample each other. It is horrible.
The MK hub can be a little scary post-fireworks, when folks are cranky and in a rush to leave.