As soon as they heard the gunshots Friday night at Krokos City Hall, Efim Fidrya and his wife ran to the basement of the building and hid with three others in a bathroom.
They listened as the gunfire began and thousands of people who had come to a sold-out rock concert on the outskirts of Moscow began screaming and trying to leave.
Terrified and scared, Mr. Findrya did the only thing he could think of: He held tightly to the bathroom door, which didn’t lock, trying to protect the group in case the assailants came for them.
“While we could hear gunshots and screams, I stood the whole time keeping the bathroom door closed,” Mr. Fidrya, an academic, said in a telephone interview from Moscow. “The others were standing in the corner so that if someone started shooting through the door, they wouldn’t be in the line of fire.”
They didn’t know it at the time, but they were taking refuge from what became Russia’s deadliest terror attack in two decades, after four gunmen entered the popular concert venue and began firing rapid-fire weapons.
Their story is one of many harrowing accounts that have emerged in the days since the attack, which killed at least 137 people. More than 100 injured are being treated, some in critical condition, health officials said.
Mr. Fidrya’s small group waited and waited, but the attackers had set fire to the compound and it spread. Mr Fidryas’ wife, Olga, showed everyone how to wet their T-shirts and hold them over their faces so they could breathe without inhaling toxic smoke.
And then a second round of gunfire rang out.
After about half an hour, it was so smoky that Mr Fidrya, 42, thought even the perpetrators must have left. On his way out, he saw the body of a dead woman lying next to the escalator. Later she saw the body of another woman who had been killed in the massacre, her distraught husband standing over her.
His team went down to the garage and eventually out onto the street as emergency workers carried victims out of the building.
Islamic State, through its news agency, claimed responsibility for the attack. US officials said the attackers were believed to be part of ISIS-K, an offshoot of Islamic State in Afghanistan. On Saturday, Russia’s Federal Security Services announced that 11 people had been arrested, including four who were arrested after the getaway car was intercepted by authorities 230 miles southwest of Moscow.
In interviews, survivors described how what started as a typical Friday night out turned into a scene of panic and terror. The 6,200-capacity venue was sold out for a show by a veteran Russian band called Piknik.
Video from the scene shows the gunmen shooting at the entrance to the concert venue, part of a sprawling, luxury complex of buildings that also includes a shopping mall and several exhibition spaces. They then moved into the concert hall, where they also fired shots, as the videos show.
The attackers also set fire to the building using a combination of explosives and flammable liquids, Russian authorities said.
Like the Fidryas, Tatyana Farafontova initially thought the sound of gunfire was part of the show.
“Five minutes before the start of the show, we heard this dull applause,” she wrote on her VK social media page. Ms Farafontova, 38, said in an instant message on Saturday that she was still in shock and slurred her speech after the attack.
Then the applause got closer and someone shouted that there were attackers shooting. She took the stage with the help of her husband.
“The moment we went on stage, three people entered the hall with machine guns,” she wrote on her VK account. “They shot everything that moved. My husband from the stage saw bluish smoke filling the hall.”
Ms Farafontova said being center stage made her feel exposed and targeted.
“It felt like I was being hit in the back with the muzzle of a machine gun,” he wrote, adding, “I could feel the breath of death right behind my shoulders.”
He crawled under the curtain and finally followed the musicians, who were already starting to leave, and ran as far away from the building as he could.
Up on the balcony, Aleksandr Pyankov and his wife, Anna, heard the shots and lay on the floor for some time before joining others who jumped up and started running for the exit.
As they fled, they encountered a woman who had collapsed on an escalator and was blocking their way. She was alive but looking doubtfully ahead, said Mr Pyankov, a publishing executive. He told her to keep running, but then he turned his head and saw what she was looking at.
“I started looking,” Mr. Pyankov, 51, said in a telephone interview. “And first I saw a murdered woman sitting on the sofa and there was a young man lying next to her. I looked around and there were groups of corpses.”
It all happened in a matter of seconds, he said, and tried to keep running.
“The worst thing is that in this situation you are not running away from the shooting, but towards it,” he said. “Because it was already clear there was going to be a fire there, we know how it was going to burn. And you just run to find somewhere else to run.”
Anastasiya Volkova lost both her parents in the attack. She told 5 TV, a state channel, that she missed a call from her mother on Friday night around the time of the attack. When she called, there was no answer, Ms. Volkova said.
“I couldn’t answer the phone. I didn’t hear the call,” Ms Volkova told the broadcaster, adding that her mother was “really looking forward to this concert”.
Accounts that emerged of others who died in the attack also told stories of eager spectators who had gone to great lengths to get to the show.
Irina Okisheva and her husband, Pavel Okishev, traveled hundreds of miles – making their way from Kirov, north-east of Moscow. Mr Okishev had received the tickets as an early birthday present, Komsomolsaya Pravda newspaper reported. He did not live to celebrate his 35th birthday, which is this week. Both he and his wife died in the attack.
And Alexander Baklemyshev, 51, had long dreamed of seeing Piknik, a heritage rock band playing the first of two sold-out concerts accompanied by a symphony orchestra.
Mr Baklemyshev’s son told local media that his father had traveled alone from his hometown of Satka, about 1,000 miles east of Moscow, for the concert.
His son, Maxim, told Russian news agency MSK1 that his father had sent him a video from the concert hall before the attack. That was the last she had heard from him.
“There was no final discussion,” his son said. “All that’s left is the video and nothing else.”
Mr Fidrya said he was grateful to be alive and that four of the attackers had been arrested.
“Now there is confidence that the crime will be solved and the non-humans who organized and committed it will be punished,” he said. “That really helps a lot.”
However, the images of the victims remain etched in his memory, particularly that of the husband, his back burned by the fire, standing over his dead wife outside the building as medics attended to the wounded.
The man was talking to Mr Fidrya’s wife, Olga, saying they were from the city of Tver north-west of Moscow, had been together for 12 years and had three children.
“It’s all over for us, by and large,” Mr. Fidryas wrote in a message after the phone interview. “But for that guy who stood over the body of his wife and their three children, the worst is yet to come. And there are so many people like him there.”
Oleg Matsnev contributed to the report.
