(CNN) -- It was the middle of the day, and The Mall in Columbia was packed. Packed with parents pushing around strollers. With teenagers sharing some laughs. With shoppers dipping in to pick up something special.
"Just a regular day," said Colin Ready, a worker at one of the Maryland mall's stores.
Then came a boom. Moments later, "boom, boom, boom."
"Then I saw everybody running," Ready told CNN.
What they were running from was a multiple homicide. Police said that a gunman shot dead two employees at Zumiez -- a skate shop that also sells shoes and clothes for men, women and children -- before killing himself.
Hours later, Howard County Police Chief Bill McMahon said officers who arrived at the store within minutes of the first 911 calls at 11:15 a.m. found three people dead.
The shooter, who'd apparently killed himself, was found alongside his shotgun and "a large amount of ammunition."
But no one inside the mall 20 miles southwest of Baltimore had any idea the bloodshed was over.
"No one knows what's going on," said one worker at the mall, identified only as K.T. "In today's world, you hear gunshots and you run."
Ready recalled about eight or nine shots ringing out, as well as the chaos outside his store.
"Everybody was screaming," he said. "There were kids running around. I saw an older couple, I guess they couldn't run or anything so they were just crouched (down) to try to get cover."
K.T. remembers "a lot of kids ... crying, and mothers were holding onto them."
It was "crazy," surreal, all those cliche words you use when terror visits a place where you'd never imagine it.
As K.T. put it, "It's one of those things you see on TV but never expect you'll go through."
Some got safely outside, a diverse array of Saturday mallgoers, young and old, with families and without, who boarded buses to take them away from what was now a crime scene.
Many worriedly clutched hands with those they were walking with, some choking back tears as they talked on the phone.
Others, though, didn't or couldn't leave.
Judy Hoffman was among them. She locked herself inside the back room of a store she worked at, turned off the lights and waited.
Ready said he and his store's assistant manager hunkered in a stockroom for about 45 minutes before a man who -- without a uniform or badge -- identified himself as a Howard County police officer knocked.
"We didn't know whether to believe him or not, so we were really scared before he decided to open the door," Ready said. "But he did. It was him. He let us out, and then it was safe."
Another woman who worked at the mall, Shannon Washington, told CNN she he hid behind a counter for "a couple of hours" before being escorted out by law enforcement then combing the mall.
Washington eventually got home, the impact of the shooting lingered. She couldn't think of going back to work, knowing she could find herself at any point in the middle of something this horrible, this frightening, this unexpected.
"This is the world," said Washington. "It seems like every time I turn on the news, it seems like this kind of thing is happening."
CNN's Ray Sanchez and Ralph Ellis contributed to this report.