SEOUL, South Korea (AP) — The narrow street in Seoul’s popular Itaewon neighborhood was already packed with people celebrating Halloween as high school student Eunseo Kim and her friend pushed themselves into the crowd. Lines of people waiting for their faces to be painted or to get into restaurants slowed the flow of revelers walking through the party zone in South Korea’s capital.

As the 17-year-old slowly worked her way up the narrow alley on a hill, the crowd became increasingly compressed.

“Women were repeatedly saying ‘please don’t push,’ as men were saying ‘push, push,’” she recalled. She began struggling to breathe as her chest was crushed.

Then she lost her balance and fell.

On the ground, Kim felt like she had become invisible to the crowd. People stepped on her ankle, wrist and calf, and she remembers thinking she was going to die.

Incredibly, she survived, but at least 156 others were killed in the crush Saturday night, 101 of them women, primarily in their teens or 20s, according to figures released Tuesday by the Interior and Safety Ministry.

Because they are often shorter and less physically strong than men, experts say women are particularly vulnerable during “crowd turbulence” situations similar to what unfolded in the Itaewon alleys on Saturday, when the density of a crowd hits a tipping point and leads to a deadly crush.

“Five to 10 centimeters in height makes a big difference when it comes to chest pressure,” said Choi Sukjae, an emergency medicine specialist and public relations director of the Korean Emergency Medical Association.

At about 172 centimeters (5′ 8″), Kim is taller than many other women in South Korea but still vividly recalls having the breath crushed out of her as people stuck their elbows out protectively and pushed into her chest.

“People were pressing me from both ways; my chest was compressed,” she said.

A dramatic video shot in an alley around the corner from where Kim was shows a handful of men managing to wind away from the suffocating crush. One man pulled himself up and out of the crowd by scaling the face of a building, then climbed across its illuminated sign and dropped back to a less packed part of the street, out of danger’s way.

More than 100,000 people are thought to have been in the Itaewon streets on Saturday. Hwang Minku, a video forensic expert, said it is difficult to discern the makeup of the crowd from the aerial images of the scene.

Complicating the situation further, many wore costumes that made it hard or impossible to determine their sex or approximate age, though Halloween celebrations in South Korea tend to draw younger crowds.

What is known is that of the 156 people killed, 12 were teenagers and 104 were in their 20s, according to the Interior and Safety Ministry. Thirty-one others were in their 30s, eight in their 40s, and one was in their 50s. Fifty-five were male and 101 female.

Of 151 additional people who were injured, 29 remain in critical condition.

Dirk Helbing, a professor of computational social science at ETH Zurich university who studies crowd dynamics, said the numbers of women and young people killed were “shocking” and needed to be further investigated before drawing final conclusions.

“I do not recall having seen any numbers in the past that (broke down) victims by gender or age,” he said. “The disaster shows that we are all vulnerable, perhaps to different degrees.”

Helbing has extensively studied Germany’s 2010 Love Parade disaster, in which 21 people died as they tried to exit through a bottleneck in a “crowd turbulence” situation he said had “striking similarities” to the tragedy in Seoul.

Crowd turbulence occurs when the group’s density is so high that movement becomes fluid, with people pushing into one another involuntarily and transferring force between their bodies.

“These erratic forces cause a turbulent pattern of motion of the crowd … (and) someone might stumble, thereby creating a hole in the crowd,” Helbing said in an email.

When that happens, people nearby no longer have the counterforce of the person in front of them and fall themselves, creating a domino effect as more and more people fall on top of each other, he said.

“It does not require any relentless behavior of other people or a readiness to hurt people,” he said.

‘In fact, in many cases of critical crowd conditions, many people are trying to help each other, but the situation may be desperate, and not even police or first aid units may be able to prevent the disaster from happening once crowd turbulence occurs.”

Ken Fallas, a Costa Rican architect who has worked in Seoul for the past eight years, was about 30 meters (yards) from the alley that was the center of the crush at its peak. He remembers a feeling of helplessness as it unfolded.

“It is not something that you can control,” Fallas said. “Most people will think, like, no, if I will be in that situation I will just push back — there’s no way to push back — we’re talking about probably 300 people behind you and the pressure of 300 people … to push back is impossible.”

Deeper into the alley where Fallas was trapped, Kim said that after she fell, her friend desperately tried to grab her but then disappeared into the crowd.

“I kept hearing people saying ‘push, push’ from the back, and people fell,” she said. “My friend tried to grab me and got swept away. It was as if a tsunami had swept them away.”

But she was one of the lucky ones, managing to get back to her feet with the help of a man in a police costume, and found her friend by a roadside club’s stairway.

A club employee pulled her and others inside and helped them escape through the back door to safety.

Even having been that close to where most people were killed, Kim didn’t realize anyone had been seriously injured until she saw a row of ambulances as she exited the club.

“I saw people on stretchers getting carried out and heard screaming,” she said. “But some people still thought the ambulances were part of the Halloween setup.”

Days later, she said her heart still races when she hears ambulance sirens, and she feels claustrophobic even in a group of people in her school cafeteria.

“Friends at school talk about the Itaewon tragedy, and it’s very difficult for me to listen,” she said.

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Tong-hyung Kim in Seoul and Kiko Rosario in Bangkok contributed to this story.