Corbin Dates, 23, was bored during his job at an AT&T call center Thursday afternoon, reading online about the Batman premiere, and he decided to book a ticket through Fandango on his cellphone. He went home to Aurora for dinner, went to the gym and dressed in gym shorts and a T-shirt.

He arrived at the theater at 11:30 p.m. to find only a few empty seats. He sat down in the second row, near the right aisle. Only one person was in the front row, he said, directly in front of him in the last seat on the right. Just before the previews, this person answered — or pretended to answer — a cellphone call and then walked out the emergency exit, propping the door with a stick. Dates didn’t think anything of it until later.

The movie started. The audience applauded. High school kids in the back of the theater were “being annoying,” he said, yelling and making jokes. He could hear beer bottles rattling on the floor around him, even though alcohol wasn’t allowed in the theater.

About 20 minutes into the movie, the emergency exit door swung open. The floodlights from the parking lot created a glow in the dark theater. One guy stood at the door, wearing a gas mask, looking like a SWAT person. Only his eyes were visible. He didn’t say anything, and for a few seconds he just stood there, like “a guy who showed up late for his own party, a dramatic moment,” Dates said. He thought it was a stunt, a promotion for the movie, but then the person at the door stepped in front of the screen and threw a canister into the center of the theater. Then he fired one shot at the ceiling, and Dates dived to the ground.

The shooter walked up the right stairs of the theater, past Dates and others in the front few rows. He started shooting as he walked up the stairs, shot by shot, a few seconds between each one. Dates was lying face down on the floor, next to three or four other people. He slid under the first row of seats and arm-crawled toward the left exit. His experience of the shooting was mostly auditory: The movie continued to play in the dark theater, but over the sounds of the movie were the shooting and screaming. Women’s screams mostly. Someone crawling in front of Dates screamed, and he grabbed her and told her to keep quiet.

As they crawled under the seats, hot gun shells slid across the theater floor and hit them. Dates suffered two inch-long burns on his right calf. His knees were scuffed and bruised from crawling across the polished concrete floor.

“I’m just thinking, ‘Forget about the burns, stay calm, stay calm,’ ” he said. “The sounds were the worst part. I could look at the floor and choose not to look, but you had no choice but to hear it — it was hysterical. You would hear the bang of a shot, and then pleas, and shrill screams, and people scrambling over seats and falling. Everyone was coughing. The woman in front of me was having a panic attack, screaming that she had asthma.”

The only silence came from the shooter, he said. The shooter didn’t speak, didn’t make any dramatic gestures. He just moved through the theater and fired methodically.

Dates said that some of the people crawling in front of him ran out the left exit, but they turned back inside because they said the shooter had come from the right side of the theater to meet them at the exit, and he was shooting people attempting to leave. So Dates stayed in place under the seats, now on the left side of the second row, on the opposite end of the theater from his original seat.

After several minutes of shooting, there was a moment of silence, and Dates scrambled onto his knees to look at the theater behind him. It was dark and smoky, but his eyes were fine; they weren’t burning. He saw bodies slumped over chairs, a teenage girl lying limp near the aisle. One person was hiding in the theater curtain. There was a white man, maybe 25, bleeding near the left exit.

During the silence, Dates arm-crawled out the left exit. He said he was one of the last people to leave the theater. He guesses that the shooter had also left by then, although he isn’t sure. As he exited, policemen with guns were pushing their way in, arriving on the scene.

The lobby was chaos, and Dates started to panic. “It was like I had held it together for as long as I could,” he said. He sprinted out of the theater to his Jeep. Cars were waiting to exit the parking lot, and Dates swung his Jeep into four-wheel drive and drove up onto a grassy hill, around the line and directly to the road. He went straight to his mom’s house. He stayed there for an hour and then drove to Gateway High School to give a statement to police.