A “lull” swept over Orlando Regional Medical Center’s emergency room after doctors and nurses tended to nearly two dozen patients who were rushed there about 3:30 a.m. Sunday — all with injuries inflicted by a lone gunman at a nearby dance club.

About two hours later, a second wave of just as many were hurried through the doors at Central Florida’s only Level One trauma center — stunning doctors and hospital staff just as it did law enforcement minutes earlier who discovered them as they scoured the scene three blocks south at Pulse.

The initial known death toll — which, in the immediate aftermath of the terrorist attack, stood at 20 — instantly grew more than twofold to 49 after law-enforcement ended a standoff by ramming their way into Pulse, an LGBT-centered nightclub, where the deadliest mass shooting in U.S. history had just unfolded.

The victims were piled into every available vehicle by “truckloads” and “ambulance-loads” for a less than a two-minute drive to the hospital, according to Dr. Michael Cheatham, who spoke at a news conference at the medical center Tuesday morning.

The sheer amount of blood and chaos created “a war scene” inside the hospital, said Dr. Joseph Ibrahim, a trauma surgeon. He described several bleeding patients who were rushed to the hospital in the same ambulances, one after the other, until the emergency room was packed with people suffering from “a full gamut” of wounds to their chests, pelvises, abdomens, and extremities, some with a “significant amount of tissue destruction.”

Doctors said they scrambled to identify the gunshot wounds to determine the bullets’ courses, some from small and others from large-caliber ammunition. Most were shot from below; some were shot at close range, others, at a distance while trying to flee the rampage.

“The operating room would fill with a patient and we would proceed with operative intervention, whatever was needed and literally walk from that operating room to another operating room and do it again and again,” Dr. William Havron, the general surgery program director and a trauma surgeon, said.

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All the victims’ cases were “close calls,” one doctor said, adding, “If they hadn’t been three blocks to the hospital, they may not have made it to a hospital.”

Dr. Chadwick Smith appeared visibly upset as he choked back tears while he described calling in additional staff members — some who had just finished full shifts and others who were on vacation — telling them, “This is not a drill, this is not a joke.” He said everyone answered: “I’ll be right there.”

Before the sun came up Sunday morning, a total of 44 victims made it to the hospital — nine of them dying within minutes of arrival — leaving 35 under the staff’s care. As of Tuesday morning, 27 of them remained in the hospital, six were still in critical condition and “remain critically ill,” while five others remained in “guarded condition,” doctors said. All who sustained gunshots to the head had died, except for one, who is being treated in the intensive care unit.

“Like I said from the first day, I would be surprised if we do not see the death toll rise,” Dr. Havron said. So far, none of the patients treated had died.

The hospital, which one doctor labeled as the “busiest trauma center in the state,” attends to 5,000 trauma victims a year, about 20 percent of them under the umbrella of “penetrating trauma” such as gunshot wounds.

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And although the doctors, nurses and support staff had prior large-scale events that sent numerous patients through the hospital doors at the same time — like hurricanes — the gravity of Sunday’s terror attack and the loss of life left its mark, prompting the availability of grief counseling.

“I was walking out of the hospital and, walking out, I saw team members walking into work crying,” one doctor said. “I just couldn’t express how hard it is. . . . but when the task comes to hand, you just do what needs to be done.”