Highland Park shooting witnesses describe shock and horror

Eyewitnesses who scrambled for their lives after a gunman opened fire at the Fourth of July parade in Highland Park, Illinois, described a frightening, chaotic scene Monday.

Zoe Nicole Pawelczak told ABC News that she attended the parade with her father, and at first, they thought they heard fireworks.

But Pawelczak quickly realized something was wrong.

"It was like no fireworks that I heard," she said.

Pawelczak and her father ran for cover and hid behind a dumpster. There they found a man who had placed his two young children inside the container.

"He said his other son was lost on the streets. He said, 'I have to go find my son. Can you watch my kids?' So I watched his kids for him," Pawelczak said.

"They were like 'What's going on?' And I was like 'It's just fireworks, it's OK,' just trying to keep them calm. And we just hung out in the dumpster for a bit."

Pawelczak said she didn't immediately know if the man found his son.

Pawelczak said she later took shelter inside a sporting goods store as the police ordered a lockdown. She said she hugged a woman who was in tears.

"So many people came in and they were just screaming a certain name of a loved one who they were separated from," she said.

Jon Will attended the parade with his 97-year-old mother who uses a wheelchair. Like others, at first, he thought the gunshots were fireworks -- but he quickly realized it was gunfire.

"Everyone just got up and got the hell out of there," he said.

He and other family members pushed his mother into an alley, where they hid out. Once they felt it was safe for them to keep moving, they walked a few blocks to a relative's home.

"This doesn't happen in a little town like this. Just unbelievable," Will said. "It's scary. I don't know what this world is coming to. It's ridiculous."

Dr. David Braum was at the parade with his daughter, son-in-law, and grandson, and told ABC News that people were horrified at the sight of the carnage.

"I would say without having served in the armed forces, these are the kind of injuries that are seen in war," he told ABC News.

Braum said he and others with medical training jumped in to help treat the injured.

"It seemed as if the shooting had stopped, there were a couple minutes of lull, and then people did whatever they could. They applied a tourniquet. I started a couple of IVs. We helped move people to a staging area," he said.

Braum also expressed his frustration with the latest in a string of mass shootings that have gripped the nation.

"Being a physician I’ve seen bad things, but I don’t think the average person could," he said. "That the image of what was there today, the average person would have a hard time forever forgetting."

ABC News' Alex Perez contributed to this report.