Three people suffered minor injuries when the woman barreled completely through the Mission Viejo store at about 5 p.m. Tuesday.
"This is the craziest thing that's ever happened," Bain said Thursday from the Rock N' Road Cyclery, where he is manager.
The elderly driver, who was not cited or immediately identified, told authorities she was parking in a handicapped space in front of the store when she accidentally hit the gas pedal instead of the brake, Orange County sheriff's spokesman Jim Amormino said.
Bain said three customers and five employees were in the store when the 2001 Cadillac Deville and smashed through the glass front door. He estimated the car was doing 30 to 40 mph.
The store had reopened this week after a $300,000 remodeling, Bain said.
The car destroyed about $30,000 worth of merchandise and caused about $20,000 to $30,000 damage to the store, he estimated.
"It was weird, it was like blur," he said. "It was so loud...The squeal of her tires. She actually burned out when she took off. It was like someone catapulted her."
Bain said he was about five feet away but other staff barely escaped with their lives.
Store surveillance video posted on YouTube shows a man and a woman on crutches frantically jumping back against a counter a second or two before the car zooms past them, scattering merchandise and narrowly missing them.
The car continued some 100 feet or more through the store, plowing through a concrete wall into a newly built studio and slammed into the back wall with the back wheels still spinning.
When store employees reached the woman, she still was pushing the gas pedal to the floor. The car was leaking some kind of fluid and the spinning tires had melted a hole in the floor, filling the store with smoke.
The woman at first did not want to leave the car because she could not find her purse but eventually she was persuaded, Bain said.
Her adult granddaughter also was in the car.
They both seemed stunned after the crash, Bain said.
"The car was so wedged into the back of the store they had to get a winch and pull it out," Bain added.