As the conflict raged, Dr Ibrahim Hisham managed just one hour's sleep on his busiest night in the makeshift field hospital at a mosque just off Tahrir Square.
"They have no mercy," he said of the pro-Mubarak forces that started the pitched battle by attacking protesters in the square on Wednesday.
Most of the injuries were from rocks, but he estimated the number of gun shot wounds at 50 and said he knew of three protesters who had died from their injuries: one in the temporary hospital, one outside in the square, and one in a city hospital to which the medics had managed to refer him.
Although he is a strong supporter of the anti-Mubarak protests, he also treated an injured soldier during the night and would unhesitatingly treat an injured pro-Mubarak demonstrator if the situation arose.
"I am a doctor first," he explained. And indeed this cramped and busy unit makes up in medical professionalism what it lacks in clinical standards of sterilisation.
Dr Hisham, a senior ear, nose and throat and laser surgery expert from Cairo University Hospital, is one of more than 100 medical volunteers treating the wounded, some of whom were still lying under blankets on the ground yesterday morning.
Bandages were being stored in the pigeonholes normally reserved for worshippers' shoes. As used cartons of drugs – many of them originally brought by supportive members of the public – were being piled by paramedics into plastic bags, a volunteer was sweeping carefully around the patients to try to keep the floor clean.
Outside, in an overspill clinic on the square, another white-coated doctor was stitching the wound of another protester. One of Dr Hisham's hospital colleagues, Dr Ashraf Said, a paediatrician and internal medicine specialist, said he went to the field clinic for the first time yesterday after pitched battles in the square. He said it was also an act of solidarity.
"I came to support the protesters, to change the President." He explained that the medics had managed to separate the small and crowded space into separate units, including ones for minor general surgery and emergency triage, a pharmacy and even an makeshift intensive care unit.
Another doctor, who preferred not to give his name because he works in a government hospital, acknowledged that some anti-Mubarak protesters had thrown stones in self-defence but said it was clear that their attackers had been much better armed.
Unlike his two secular colleagues from the University Hospital, he is a Salafist in religious terms, but not an adherent of the Muslim Brotherhood, though he says he respects them. One of his closest colleagues at his hospital was a Christian. It was not true, he said, that those engaged in the battle on the protesters' side had all been "Islamists or fundamentalists". He had even seen a teenage girl, who clearly was neither, breaking up paving stones.
One patient, Mustafa Magdi, a fourth-year student at Ain Shams university in Cairo, was undeterred by the wound from a stone to his now amply bandaged head.
Yes, he said, they had thrown stones back, but only after they were attacked. "We have been here for 10 days and we didn't do anything." Asked if he had a preferred candidate to succeed Mr Mubarak, he replied: "It will be someone we choose. Let him go first and then we will decide. But I am not going from here until he goes. Tahrir Square is ours."