"Everything went berserk," he said.
Authorities say 23-year-old Arris Pitmon leaped through the window of the Atlanta bus, overpowered the driver to take the wheel and then left the bus driverless as it thundered down a steep hill.
A dozen or so screaming students were on the bus as it plunged, many bounding out of the emergency exit in the back, said Atlanta Public Schools spokesman Keith Bromery. Two students and the bus driver suffered minor injuries, police said.
By the time Pitmon was arrested after the crash, he was naked, police said. Turner, who had rushed to the scene, said the man lost his pants while trying to escape from bystanders.
"This was a weirdo," said Turner, who is 38. "Something was wrong with this guy. We turned him over and he just had a condom on. Maybe he was stripping or something I had no earthly idea."
Pitmon jumped into the stopped bus as a student from Forest Hills Academy, which is grades seven through 12, was being dropped off in a southeast Atlanta neighborhood, said Atlanta Police Officer James Polite. He took control of the steering wheel, then left the seat to chase the driver, who had run to the rear, the officer said.
A student tried to take the wheel, but Polite said Pitmon fought him to regain control of the bus. The bus continued forward, left the roadway and crashed through a fence, finally stopping at a wall about 175 feet off the pavement.
Turner and two of his employees bolted toward the bus after one of the girls who escaped the vehicle came to him begging for help. One of the men blocked the front door, forcing Pitmon to the back. Turner said Pitmon then slipped out the back and tried to crawl under the bus, losing his pants in the process. Turner grabbed his leg and pulled him out.
He said he stood with his foot on the suspect for about 10 minutes before police came to arrest him.
Authorities didn't say whether Pitmon had a relationship with the bus driver. The suspect was in custody but police have not said what charges he faces.
Surveillance video from a nearby Citgo gas station showed the shirtless suspect crouching and fidgeting as he walked through the lobby before jumping aboard. A cashier said Pitmon seemed to be looking for someone.
"Suddenly, he was doing crazy things," said Mohamed Gulhamid, who works at the Citgo. "He was sitting down, he was trying to grab a customer's feet."
School officials are thankful that the bizarre hijacking didn't turn out worse.
"The bus was down a steep incline. If it had jumped the curb wrong, it could have turned over," said Bromery. "It was a precarious situation." He said the incident had no impact on the school, which opened as usual Friday morning.
Turner, meanwhile, said he still can't believe what happened.
"This has been the craziest day I've ever had in my life," said Turner. "My concern was the children we had to get them out of the bus. And it's a blessing that nobody got seriously hurt."