Anyway, they are running, and there are cars and trucks at the end of the bridge to barricade/slow the flow of the chamber pot. There are armed bubbas and Ned Flanders and Clint Eastwoods from Gran Torino standing there. They STILL don't do anything, and now the humanoids have guns!
Your scenario almost happened in Detroit in 1968. My in-laws were there. The rioting made it out as far as 6 Mile. White armed suburbanites were waiting along 8 Mile.