CHICAGO (CBS)–A woman who was at Mercy Hospital Monday afternoon for radiation treatment said she and others took cover inside a utility closet as a gunman opened fire nearby.

Tracy Lyons told CBS 2 she went into the hospital from the parking lot to take cover after she saw a maroon-colored Dodge Charger exchange gunfire with police.

cancer patient Mercy Hospital Cancer Patient Recounts Terrifying Moments Hiding From Gunman Inside Utility Closet

“The shots were coming so strong, so closely,” she said. “I thought I was going to be hit by a bullet. I just got out of radiation–I can barely breathe.”

Lyons recounted the terrifying moments she hid inside the utility room, located inside the hospital’s cancer treatment center.

“It was an exchange–like ‘pow pow pow pow pow pow pow,'” Lyons said. “It was extreme and it was very loud and it was close.”

Lyons said the SWAT team arrived and led her and others safely out of the room.

“I’ve been battling cancer for over four years, so I come here on a regular basis,” she said. “When the gunfire started, me and my girlfriend jumped to the ground.”