The ambush came from the left, from a side street which led up the hill to Mokattam mosque. A rush of hundreds of men running down on the march of anti-government protesters, bringing a sudden clatter of rocks landing all around, the crack of shots fired and the whizz of tear gas canisters. Sticks, stones and metal bars flew through the smoke in both directions and screaming women and men ran back the way they came.
Dozens of manned police vans remained parked a kilometre away. The only sirens came from ambulances that drove through the crowds and past burning vehicles to take some 40 injured people to hospital.
One angry woman with a bleeding mouth and eyes streaming from the tear gas pulled off her headscarf and stood yelling at the other side, the supporters of the ruling Muslim Brotherhood: "You are not Islam! You are not Egypt! Where is my freedom?"
So go most Fridays in Cairo over the past few weeks as liberal Egyptians have shown their virulent opposition to the president, Mohamed Morsi, as he has awarded himself new powers and pushed through a deeply contentious new constitution. Several buildings of the Muslim Brotherhood, the group behind Morsi, have been burned. In post-Arab spring Egypt the revolution continues. But it's women of all classes who have found themselves most alienated – written out of the jostling for power and subjected to a skyrocketing number of sex assaults, rapes and harassment.
Women who stood shoulder to shoulder with men during the 2011 Tahrir Square protests that brought down Hosni Mubarak found their position in society undermined almost immediately. The parliamentary quota for women was removed without debate and a promised female vice-president failed to materialise, amid what political commentator Moushira Khattab called "a radical anti-feminist sentiment". Morsi threatened but stopped short of decriminalising Egypt's practice of female genital mutilation, carried out on almost three-quarters of Egyptian girls, making it clear he would not tackle an issue he called "a family matter".