AUSTIN (KXAN) — As Houston Police start their investigation into what caused the crowd to surge at Travis Scott’s Astroworld Festival, questions remain about how well-equipped the city and event organizers were to respond to a tragedy like the one Friday night.

“…Huge men screaming for help, like literally screaming,” recounts one festival eyewitness. “One girl locked eyes with me and she begged me to help lift her so she could crowd surf. But I couldn’t even move my arm to get help. I couldn’t even do that. I myself could barely even breathe.”

Doctor Guadalupe Zamora with the Texas Medical Association and Travis County Medical Society explains how getting caught in a crowd surge can end up fatal.

“People are pushing and pushing, and you got one hard substance against you and then a person behind you, and your lungs just can’t expand. You can’t get any air in,” Zamora says. He likens it to the pressure someone would feel when scuba diving.

Houston’s police chief said they’re waiting on medical reports to determine the exact cause of death for the eight who were killed, but that some fans were trampled at the festival.

Austin medical professionals say in these large events, there can be many different types of traumatic injuries — from stampedes to heart attacks.

They’re all situations Austin’s first responders prepare for ahead of their events, like the ACL Festival, says Selena Xie, president of the Austin EMS Association. She says doctors and nurses are also on festival grounds, managing what are essentially ‘field hospitals.’

“We know where– if, if there was to be a mass casualty event, where all the ambulances would need to line up and transport patients, we know how to quickly extricate patients to any given point,” she says.

Xie says that comes in the form of a briefing, and first responders also have special equipment like higher protection ballistic vests, helmets and are required to carry flashlights.

Houston fire chief Samuel Peña said a third-party contractor was handling the medical needs for Astroworld.

“They had doctors on scene, they had medical EMTs, they had volunteers,” Peña said during a press conference Saturday. “For a non-event, that would’ve been enough. But when the event started to escalate, we had to come in and augment their assistance.

But Peña couldn’t comment on whether third-party responders were equipped to handle a tragedy like this.

“From our perspective, from the Houston Fire Department’s perspective, we had the right equipment,” he said. “I can’t speak about the equipment that the third-party medical component had. I can’t speak to that right now.”

Xie says the pandemic has been a driving factor in a nationwide staffing shortage for nurses and paramedics, and worries if that may have impacted the third-party response in Houston.

“We’re gonna see a lot of these fallouts because of these type of staffing shortages; and we’ll see people use personnel that are not highly trained,” she says.

Houston leaders say fire and EMS units were stationed around NRG Park Stadium and acted quickly to help, with 62 units responding.

“They were able to step in immediately when reports of the incident occurred,” said Houston Mayor Sylvester Turner during a press conference Saturday.

Turner said first responders received those reports around 9:30 p.m. and the event was shut down around 10:10 p.m.

Xie says staffing shortages are making it more difficult to staff these mass events, saying it resulted in fewer personnel in the field at this year’s ACL Festival.

“We’re looking really strongly about how to make sure that… we’re able to prevent these type of events from happening in Austin,” Xie says.