Rena was playing on her lounge floor, in her mother's lap, when the shot tore through her cheek. She grimaced, cried for her mother and then went silent, as the blood began to flow in her mouth.
The bullet came from nowhere, bursting through the frosted-glass window on the family balcony, knocking out one of her teeth, and shattering her family's world. But in Aleppo, their ordeal had just begun because the struggle here is always to find medical help, fast.
Her neighbor - the women looking after Rena can't leave their home unaccompanied by male relatives - then rushed her to the street, carrying her body. That's when we saw him, the sight of a man carrying a limp girl still striking even amid the daily atrocities of Aleppo.
He flagged down a truck and they began to race towards the hospital. We followed, unsure what had happened. After a minute, the neighbor noticed us and clearly decided our car might move through the traffic faster. He stopped the truck he was in, leapt out and ran towards us, Rena bleeding in his arms, and screamed for help.
He threw Rena onto the back seat and told us to race to the hospital, saying, "Guys, she's choking."
Amid the traffic and blast of our horns, the sound of Rena's struggle to breathe was clear. A sucking sound, coupled with a gargle. The blood was flowing down her cheeks. Her neighbor screamed out of the window for cars to pass. After a minute that seemed to creep by, the car arrived at the hospital.
Dar Al'Shifa sees trauma every hour in many forms. But a child shot in the face still causes doctors to jolt. They raced her into the back emergency room and began to work on her face. The bullet had entered her mouth cleanly but had torn up the other side of her mouth. Soon it became clear they thought she would live. She was breathing more easily. The bandages made the wounds seem less severe.
But one problem remained. Dar Al'Shifa is in rebel territory where medical supplies are exhausted and hard to replenish. The decisions doctors take daily defy belief. In Rena's case, she could not get the surgery on her face she clearly needed there, so the doctors dared to think the unthinkable, and sent her across the front lines to the better equipped government hospital. She was piled into a truck and then vanished.
The women who were caring for her when the bullet struck - her grandmother and mother - were still at home trying to understand what had happened. On the stairs up to the apartment was Rena's blood. Inside the apartment was her tooth. In the window was the small hole that the bullet had made.
A military-trained safety adviser working with the CNN crew assessed the hole made by the bullet and the trajectory when it hit Rena.
It was clear to him that it must have been fired from one of the high apartment blocks opposite Rena's home. These buildings are inside rebel territory, but snipers - particularly those working for the infamous pro-government militia known as the Shabeeha - are thought to work inside rebel-held areas, and few could explain why the Free Syrian Army would shoot into areas that were sympathetic to it.
The glass through which the bullet passed was frosted, meaning the gunman would not have seen exactly who were his targets. But the deliberate nature of how indiscriminate this was made it all the more chilling.
The family members were, at that time, calm. They believed that Rena was getting the best of care and prepared for their hazardous trip to government territory to see her. It seemed like there had been a miraculous escape.
The next morning, we returned. Locals in the street broke the news to us. Rena was dead. It was hard to believe that the girl we had seen recover, and who appeared so free from the bullet that should have killed her, had died from her wounds. The family refused to speak to us at first. We were told the father was angry we had entered the home and feared reprisals.
After an hour, one relative met us outside. They said Rena had been rushed to two government hospitals. At each, they said, doctors had tried to help her. At each, they failed. It appears the bullet, which we did not find inside their home, had lodged inside her throat.
A sniper's bullet had killed a four-year-old girl, leaving us wondering how the violence now engulfing Aleppo will ever end, whether its civilians will ever recover life as they knew it.