CHICAGO (CBS)– A charity walk on a lovely day in Naperville on Saturday turned into a panicked run, when an active shooter drill interrupted the festivities.

A community was celebrating after raising more than $180,000 for the Cystic Fibrosis Foundation at the Great Strides charity walk, but the fun gathering was ruined by panic. Shortly after group photos were taken, Tina Homelvig said someone cried out “Run, there’s an active shooter.”

“My heart did start racing. I thought what can I do to save my child,” said Homelvig, who took part in the charity walk.

The active shooter drill only lasted about a minute, but for some the panic felt much longer.

“You had terrified children that witnessed this that are scared and traumatized and they’re afraid,” Homelvig said.

Homelvig was at the event with her 6-year-old son Lucas and 9-year-old daughter Hayley.

She said they were in a group of about 1,000 people when panic hit the pavilion.

It was a drill, but they didn’t know at the time.

In a letter to the foundation, the Executive Director of the Naperville Park District apologized for the panic and anxiety the training drill caused.

The letter stated the park district tested the PA system multiple times and felt it was more than adequate to alert any and all on the Riverwalk and did broadcast on multiple and repeated occasions this was only a drill.

“Not everyone heard the warning,” Homelvig said. “I don’t understand why that occurred here, and to the length it occurred.”

Park district representatives said if they drill again, they will likely shut down the nearby Riverwalk area to avoid this scenario, but Homelvig said the damage is already done.

Fortunately, no was hurt in the miscommunication.

“I would love to hear what he’d have to say if someone did get hurt, or if a small child was trampled. This could have ended really badly,” she said.

The Naperville mayor said this will be part of future discussion in city council meetings.