I worked at the WTC. I know lower Manhattan well. IT IS A SMALL AREA. You can walk it all in 20-30 minutes. It was a tragic situation, but different from what we see in NOLA.
New Yorkers came together. As corny as it sounds, it's true. For a brief moment in history, race, income, etc. etc. didn't matter in NYC. I think people remember that, even after everything is now back to relative normal. So I'd like to think that except for isolated incidents of morons seizing the chance, the city wouldn't devolve during a crisis.