WHAT WOULD BE an unruly crowd anyplace else, in China is probably a line. There are certain techniques for dealing with this. One is to wait until you are firmly wedged between two people (breathing should be difficult) and lift your feet off the ground, allowing yourself to be whisked away. This works especially well for exiting the subway.
The other technique is to push steadily on the person in front of you. Predictably, this will earn you points with the person behind you. Still, no matter how tight the line is or how close you get to the front, someone is going cut in front of you. Either they will slip right under your nose — which they do as you briefly lose consciousness. Or else they will come up from behind — which they do while elbowing your kidney when you finally get enough room to breathe.