VFX artist Dave Fothergill used CGI to simulate what hundreds of people running into a rotating metal fence would look like. In the video description Fothergill provides some additional technical information:

Crowd dynamics test using Miarmy for Maya. Shows the new servo force feature which allows struggling animation once the agent has become dynamic. Rendered with Arnold

 

Maya is a popular 3D animation software program and Miarmy is a crowd simulation plugin by Basefount.