Let me offer a counterexample. I was in NYC on 9/11. I saw the first tower burning and I saw the second plane hit. I watched incredulously when they fell.

The entire city froze. It was the first and only time NYC went silent. No cars, no construction, no one yelling. There has to have been at least 5000 people packed into a large crowd outside of Penn station, but no one was shoving or yelling for them to open the doors.

NY actually stated like that for a while. It was surreal - it felt like a dream. But the city really did come together. People were more kind and helpful to strangers. They were more aware of their neighbors and their needs. People were handing out food and blankets on the streets, trying to get through the massive disruption. I saw no rioting, no crime surge despite the fact that emergency services were completely tied up.