An MPD officer passes in front of the Uptown theater where the new Batman movie opens in the wake of last nights' shootings in Colorado, on July, 20, 2012 in Washington, DC. (Bill O'Leary/WASHINGTON POST)

Rachel Brown used her lunch hour to stop by the AMC theaters in Largo to pick up tickets for a late-night showing of “The Dark Knight Rises.” Brown said she briefly considered not seeing the movie — especially not at night — after a gunman killed 12 people at a multiplex in Colorado.

“But then I thought that’s ridiculous,” she said. “It’s like not going to school after Columbine.”

Across the Washington region and the nation, people tried to ignore their fears and their grief as they went to see the most anticipated movie of the year, just as they had planned. Many did so warily, but they did not want a killer halfway across the country to make them cower.

Warner Bros., the studio that released the movie, did not pull the film from U.S. screens, and theater owners said showings would go on as scheduled.

One of the largest theater companies, AMC, banned masks and some costumes from its shows. “We will not allow any guests into our theatres in costumes that make other guests feel uncomfortable,” AMC said in a statement.

Police in Montgomery and Prince George’s counties and several other jurisdictions in the region said they would beef up patrols around large multiplexes.

“There will be an increased presence around some movie theaters just so the public knows we know about this and we’re trying to reassure them,” Montgomery police Capt. Paul Starks said.

A Warner Bros. official said Warner was not celebrating the film’s good reviews and box office success. “We’re not canceling anything,” said the executive, who was not authorized to speak for the company and, therefore, spoke on the condition of anonymity. But “it’s hard to feel celebratory when a tragedy like this strikes.”

The moviegoing public appeared to feel the same. People wanted to see the movie, and they went. But they went with second thoughts and even some guilt.

“There was a little bit of apprehension, I guess. ‘Is it safe?’ ” J.C. Santiago, 33, said after a matinee showing of “The Dark Knight Rises” at the Regal Potomac Yard Stadium 16 complex in Alexandria. “And you don’t really think about that kind of stuff going to the movies.”

Santiago set aside those misgivings because he is a longtime Batman fan, one who first encountered the superhero in DC Comics. But he was somewhat wary when he saw an usher with a flashlight checking the exits, and his thoughts returned to Colorado.

“I took notice of it,” he said.

Many people who decided to see the movie said there was nothing anyone could do to stop a crazed gunman bent on violence.

Benjamin Lowe, 24, a University of Alabama student visiting the area, was going to the movies in Arlington County. “It could have happened in Alabama,” he said of the Colorado shootings. “It could have happened up here. You never want to hear anything like that, but at the same time, what can be done about that? How far can you go without stepping on people’s rights?”

When Casandra Stapleton, a fan who downloads Batman comic books onto her cellphone, arrived at the Regal Ballston Common 12 multiplex in Arlington, she was excited about going to the 1:40 p.m. showing of “The Dark Knight Rises.” Then her boyfriend pulled up the news from Colorado on his phone.

As Stapleton, 23, learned more about the Colorado shootings, two details in particular disturbed her: The Aurora theater where the shootings occurred was one that she and her boyfriend had often attended before leaving Colorado three months ago, and friends still in Colorado had mentioned going to the midnight opening there.

“I don’t know if they changed their minds at the last minute,” Stapleton said. “I have to call them.”

Before moving to the D.C. area for work, the couple lived in Aurora for 21 / 2 years. In that time, they said, they saw a movie at the theater by the mall at least once or twice a month.

Stapleton and her boyfriend said what happened in Colorado could happen anywhere.

The couple had no plans to return their tickets, and they spoke nostalgically about the 1960s “Batman” TV series — the one with words like “Pow!” and “Bam!” erupting on the screen. They were too young to see the show when it originally aired, but they caught it on reruns. “I grew up with Batman,” Stapleton said.

Richard Baldwin, 48, a nurse who brought his 10-year-old son, Jaden, to the Regal theater complex in Alexandria, said he was shaken by the mass shooting in Aurora but considered it a random event.

“I think it was beyond mean and crazy to do something like that,” Jaden said.

Like other moviegoers, Baldwin said he struggled to understand what the latest mass shooting says about American culture.

Some wanted to debate gun control. Some wanted to blame the diet of extreme violence served up by Hollywood and video game makers. But almost all of them wondered: What is it about America that fantasies of mass violence too often come true?

“It’s American culture, blockbuster movies in summer,” Baldwin said. “You don’t expect to get shot.”

Alexander Baldinger, Lisa de Moraes, Theresa Vargas and Ovetta Wiggins contributed to this report.