I lived in Cairo 2007-2009 and went to the big Cairo derby a few times, scarier than anything here, not totally surprised it's happened. The rivalry is deep and violent and remember they don't drink, just as well as I was standing on my balcony the night Egypt won the last African Cup of Nations while all around me the neighbours were firing Kalasnikovs and handguns into the air, a few miles away the army were firing artillery shells into the desert, they might have hit someone, they might not. Life is cheap in Egypt, like I said, not totally surprised.