LAS VEGAS >> At the main entrance of last weekend’s country music festival, Darla Christensen was checking concertgoers’ bags and boots for alcohol and contraband and was inspecting wristbands. In the crowd, her co-workers were dealing with drunken fights, fence-jumpers and patrons who wanted to go backstage.

Then the gunfire broke out.

Christensen grabbed other guards and patrons and pushed them toward a side gate. She and co-workers at the private security firm Contemporary Services Corporation lifted people over barriers and hid them behind pillars and under the stage. One of its guards was among the 58 people who died.

The 200 yellow-clad security guards who staffed the Route 91 Harvest festival played a large role in responding to the massacre — and many are returning to work security this weekend.

Christensen put on her uniform Friday to work a UFC weigh-in, her first event since the shooting. She took a backroom role where she wouldn’t have to interact with the public.

“Even just going, even just getting dressed, was hard,” she said. “It was really tough.”

Las Vegas is home to a large workforce of security guards because it hosts so many events: concerts, title fights, conventions and even a lantern festival that survivors of the shooting are staffing this weekend.

Jay Purves, the vice president of CSC’s Las Vegas branch, said private security guards — “the yellow shirts,” as he calls them — are not always taken seriously because they aren’t law enforcement.

“We’re the ones often in the background, in the shadows, but we were actually the ones right there in the thick of it all,” he said.

The staff was already unsettled before the shooting because a drunken attendee had punched one of their guards in the face Saturday, putting the guard in the hospital.

Supervisor Cheryl Metzler was working Sunday in a command center that resembles a shipping container, watching the concert on seven large surveillance monitors, when someone called to ask if there were supposed to be pyrotechnics at the show.

As people began to flee, the guards fanned out across the venue, coaxing shell-shocked concertgoers too frightened to move to head to a safer spot.

Early in the chaos, Purves got a call on his radio: “Erick’s been hit,” referring to 21-year-old employee Erick Silva.

Silva, assigned to the front of the stage, was shot in the head while helping people climb over a barricade.

Purves started running to him. On the way, he got another call on the radio. A second guard, Jeff Bachman, was shot in the leg.

As the gunfire continued, Purves and the other guards flipped over a bike rack and used it as a gurney for Silva, who was gasping for air. They carried him out to emergency responders before running back in to continue the evacuation of 22,000 people. Silva died Tuesday.

“It was complete carnage and chaos,” Purves said.

Metzler and others were trapped inside the command post, watching the surveillance screens in horror as more shots rang out, including one that injured a third guard.

“What I had seen on those TVs — no one should ever see in their life. But I wish everybody could have seen what I’d seen with our people,” she said. “Our people, they didn’t run.”

As Christensen helped pull people to exits and stopped traffic to allow people to flee, she thought of her two sons, who were also working as guards at the event.

She heard calls coming in on her radio: “Multiple bodies down, stage left. Multiple bodies down, stage right. Multiple bodies down in the field.”

Her voice broke as she recounted the moment her 20-year-old son, Ryan, ran up and hugged her.

“I was just so relieved that at least one of my children had survived this,” she said.

She was later reunited with her other son, who also escaped the gunfire.

Purves credits police, firefighters and other first responders with helping save lives Sunday. But the private security guards, “they’re the forgotten ones,” he said.

“These are working men and women who make 10, 11, 12 bucks an hour, who are in the thick of everything and have to deal with intoxication, evictions, fake tickets, complaints that the beer is too hot and the hot dogs too cold,” Purves said. “The yellow shirts are the ones people go to for help.”

Law enforcement officials hailed Jesus Campos, an unarmed security guard at the Mandalay Bay hotel casino, as an “absolute hero” for alerting officers to the gunman’s location despite having been shot in the leg.

The company is offering counseling to its employees and helping Silva’s family with his funeral. Some guards are taking a break to deal with the trauma.

But others, like Metzler, wanted to be back on the job. She considers her co-workers family.

“I want to be with my people to talk about it. If I’m just sitting home, I’m watching the TV and I don’t turn it off,” she said. “So this is the best therapy and the biggest reason I wanted to come back.”