It was a Tuesday. The morning text from Pam, the nurse who supervises the children’s unit at our hospital said that we had no beds open and that “early discharges will be appreciated.” I spent the morning rounding with my team of resident physicians, going from room to room, examining sick or injured kids and planning for the day. This toddler, whose lungs were still fragile from premature birth, would need more time on oxygen. This teen-ager’s liver had recovered from an overdose, and she was waiting for a bed at a psychiatric hospital. This baby’s seizures had slowed down. I am a pediatric hospitalist at the Level 1 trauma center for children in South Texas, the University Hospital in San Antonio, and many of my young patients are recovering from injuries: burns, car wrecks, gunshot wounds. In 2020, for the first time, firearms were the leading cause of death for American children.

At noon, we were sitting around a table together, eating bits of leftover bagels and reviewing plans for kids we hadn’t seen in person yet. At 12:17, my phone rang. It was Dr. Veronica Armijo-Garcia from the pediatric I.C.U. “This call just came in, and I don’t think it’s hit the news yet. We need to get ready for a pediatric mass casualty.”

She said there was an active shooter in an elementary school in Uvalde. Uvalde, with the big oak trees in the center of town. Something like an hour and half away from San Antonio. Their high-school softball team beat my high-school softball team. We were the closest hospital by far with a pediatric trauma-surgery team, with a pediatric I.C.U. and pediatric anesthesiologists, blood-bank resources, and all the other things you would need to save the life of a child with a gunshot wound.

Armijo-Garcia didn’t know how many kids would be coming. It seemed that the shooter was still in the building. “We need you to clear beds,” she said. “We’ll move our more stable kids out of the I.C.U. to you.”

“We’ll get right on it,” I said. The call lasted a minute. I looked up, and my team was silently staring at me. “We need to get ready for a pediatric mass-casualty event,” I told them. “There is an active shooter at an elementary school in Uvalde.” They were still silent. I realized that I needed to teach these young people how to get ready to care for a huge influx of children with gunshot wounds.

Everybody in a trauma hospital has a role in a mass-casualty event. The trauma surgeons get ready to save lives in the operating room. The I.C.U. doctors accept transfer calls and prepare to care for kids after surgery. The anesthesiologists come in. The emergency-room teams clear trauma bays, ready blood and oxygen. The nurses make everything happen safely. Respiratory therapists go to the E.R., environmental-services workers clean rooms as fast as possible, pharmacy prepares meds, the blood bank gets ready. After the mass shooting in Sutherland Springs, in 2017, our hospital leaders made a plan to send blood directly to the site of such events.

“Our role is to discharge stable kids to make room for injured kids,” I said to my team. “The I.C.U. will send kids to us, and we will take care of them so they can take the wounded kids.”

We ran through the list, quickly deciding who we could safely send home, and who we could send from our intermediate-care unit to the regular unit, to make room for I.C.U. patients. I asked one resident to call the lung doctor to see if we could send home one of her cystic-fibrosis patients. I called the rehabilitation-medicine specialist, Dr. Jeannie Harden. “There’s an active shooter at an elementary school in Uvalde, and we need to send kids home if we can.” We agreed that none of her patients were ready to go, but one of them could potentially be discharged sooner if needed.

“Let me know if you need me,” she said. “I wish I could be more useful.”

“We will need you later, very much,” I said. I meant that she would take over when the kids coming from Uvalde were ready to rehabilitate—to learn to eat again, or walk again. I was sure that we would be needing Harden.

Along with Dr. Lindsay Ercole, another hospitalist who had come directly from her son’s baptism that morning, I walked down to the coördinating nurses’ office, but the nurses didn’t know of any transfers yet. They thought maybe nine kids had been shot. One adult was headed to us with a gunshot wound. I hadn’t seen anything on the news yet. Rumors started moving fast. The residents said that fourteen kids had been shot. I walked down the hall to see one of the kids whom we were sending home, and a cluster of parents was by the nurses’ station, watching the TV. I heard a father mutter something about an elementary school. Behind him, on the TV, a reporter was live from Uvalde.

I was rattled when I walked into the next patient’s room, and asked about the baby’s breathing. “Why are you asking about that?” his mother responded, sharply. “Um, just checking in,” I said. I composed myself: this wasn’t a kid with breathing problems. “How is he doing over all?” I asked, and the conversation got back on the rails. The family felt ready to go home.

In the next room, a first-time mother was worried about starting solid foods. I sat on the bed next to her. “It’s hard when kids get a new diagnosis. You have to also remember all the ways your baby is healthy, and to enjoy the usual stuff. I wouldn’t restrict solid foods,” I said.

She smiled at me. It felt so warm and normal. I wanted to stay there. I felt glad that this mother likely had no idea why I was working to get her child out of the hospital. She did not yet know what was happening eighty-five miles away.

Lindsay and I learned that there was one kid on the way from Uvalde, routed to the pediatric I.C.U. “Just one?” I asked. We wondered whether this might be good news—maybe there weren’t too many injuries. “Or it could be really bad. It could mean that they’re all dead,” Lindsay said. But we didn’t believe that yet. I looked at the news on my phone. Greg Abbott, the Governor, had announced that at least fourteen children were dead. I didn’t believe that, either. Fourteen have been shot, I thought, not fourteen dead—fourteen had been shot, and we were waiting to receive them, patch them up, and save them.

I texted my boss, the head of the pediatric hospitalists: I’m sure you’re aware of the potential mass cas. We’re just trying to move kids down and out. She called me immediately, reminding me to focus on the needs of the kids I was already responsible for, and not discharge anyone who wasn’t safe to go home. “There are always a lot of rumors,” she said. “We don’t know how many kids will be coming, and it could take hours.” She was right. I needed to be the beta-blocker, to keep everybody’s pulse low.

Time passed. The residents told me a child had died in transport. Maybe another in the E.R. I didn’t know what was true. Radiology called with an emergency finding on a baby’s CT scan, so I huddled with palliative care and called the baby’s father. “Do I need to come home?” he asked.

I didn’t think so.

The rooms cleared, and still the children were not arriving from Uvalde. My boss texted to say that one kid was in the operating room, and two more were on the way. The news said that sixteen children and the shooter were dead.

We wanted to have never heard of them, for them to never need us. But, when that was no longer possible, we wanted the children stuffed into ambulances and helicopters, winging their way to us, filling our emergency room, spilling their blood in our operating rooms, and surviving to breathe again in the pediatric I.C.U. We wanted them here.

A few of the seriously injured children survived and are with us now. They are being treated for what Dr. Lillian Liao, the pediatric-trauma medical director and one of the surgeons who is caring for them, has called “destructive wounds,” where large areas of tissue have been removed from the body. But the mass-casualty event we had prepared for never arrived. Even overnight, my colleagues were still making ready and hoping to receive children from Uvalde. Eighteen children dead. Then nineteen. For all our preparation, our exquisite training, and our resources, we could not help them. The shooter used an AR-15-style rifle. He fired bullet after bullet into children’s faces and chests, their soft bellies, their heads. A Level 1 trauma center can do nothing for children whose bodies are so destroyed by bullets. We kept wishing to help them, even as it became clear that they were already dead.

After the publication of this article, details about patients were removed or changed due to privacy concerns.