Barely a year after surviving a massacre at a country music festival in Las Vegas, Brendan Kelly found himself in a terrifyingly familiar scene.

Kelly, 22, said he was dancing with friends at a bar in suburban Los Angeles on Wednesday night when the bullets began flying. When the gunfire was over, 12 people were dead, including a navy veteran who had lived through the deadliest mass shooting in modern US history a year ago.

“I already didn’t wish it on anybody to begin with for the first time,” Kelly said outside his home in Thousand Oaks. “The second time around doesn’t get any easier.”

Kelly, a Marine, said he heard “pop, pop” at Borderline Bar and Grill and instantly knew it was gunfire.

Here are my words: I want gun control. I don’t want prayers. I don't want thoughts.

Susan Schmidt-Orfanos, who son survived Vegas but not the LA shooting

“The chills go up your spine. You don’t think it’s real — again,” he said.

The mother of the 27-year-old man killed in the latest attack, Telemachus “Tel” Orfanos, said her son survived Vegas only to die inside Borderline, less than 10 minutes from his home.

“Here are my words: I want gun control,” said Susan Schmidt-Orfanos, her voice shaking with grief and rage. “I don’t want prayers. I don't want thoughts.”

She said she wanted Congress “to pass gun control so no one else has a child that doesn’t come home”.

At a vigil on Thursday night, survivors of both shootings gathered to honour those who didn’t make it.

“It’s hard to sleep after these kinds of things,” said Dani Merrill, who lived through the Vegas shooting and escaped the Borderline bloodshed at the bar by running out the loading dock. “You just don’t know how to feel.”

Eva Mills (right) and Holden Grzywacz, survivors of the Las Vegas mass shooting, mourn the death of Sean Adler during a vigil in Simi Valley, California, on Thursday. AP

During Wednesday’s shooting, Kelly said he threw two of his friends to the floor and covered them with his body. Then he got a look at the shooter and the terror unfolding and decided they needed to escape.

Kelly said he dragged one woman out a back emergency exit and then, using his belt, T-shirt and Marine training, applied a tourniquet to his friend’s bleeding arm.

After the shooting was over, Kelly said he and another Marine friend helped victims alongside first responders. Two of his friends were among those killed.

Chandler Gunn, 23, told The Los Angeles Times that a friend who survived the Vegas shooting works at the bar. When Gunn learned about the shooting, he rushed to Borderline.

Gunn said his friend, whose name he didn’t provide, escaped safely out the back.

“There’s people that live a whole lifetime without seeing this, and then there’s people that have seen it twice,” he said.

In social media posts, Molly Mauer said she was at Borderline and also survived Vegas.

The Mandalay Bay hotel in Las Vegas, which was the scene of the 2017 mass shooting. AP

“I can’t believe I’m saying this again. I’m alive and home safe,” she said on Facebook.

In Las Vegas and Thousand Oaks, country music fans were the victims. Borderline features country music, and Wednesday was “college night” that drew many young people to the bar. The Last Vegas shooter targeted a crowd of country music fans gathered for the Route 91 Harvest Festival.

Kelly has a large tattoo on his left arm memorialising the Las Vegas shooting, which killed 58 people. On his other arm on Thursday, he still had his wristband from the California bar.

When the Las Vegas gunman opened fire from a 32nd-floor hotel room, Kelly said he threw a friend to the ground before helping get her out of the area and into a room. Armed with a knife in case an attacker came in, he hunkered down and waited with 40 other people for four hours.

Everywhere I go, everything I do is affected. I don’t sit in a room with my back to the door.

Brendan Kelly , who lived through both the shootings

He said living through Vegas changed his life. He doesn't know how a second mass shooting will affect him down the road.

“Everywhere I go, everything I do is affected,” he said. “I don’t sit in a room with my back to the door. You’re always picking up on social cues. You’re always overanalyzing people, trying to figure out if something were to go down, ‘What would I do?’”

Kelly said Borderline had become a safe haven for dozens of Vegas survivors: “It is our home.”

A few weeks after the Vegas shooting, the bar held a benefit concert for five people from the area who were killed, and now-eerie social media posts show a number of survivors holding up a “Route 91” sign inside the bar at a six-month anniversary event.

Kelly said he’ll be looking to God for comfort in the coming weeks and months. “I know that, being a religious person, that God is never going to give me anything more than I can handle,” he said. “I’m here for a reason.”