In the wake of recent mass shootings in places like Aurora, Colorado and the Sikh Temple in Wisconsin, a debate has raged over whether stricter gun control laws might have prevented the shootings, or if a more heavily armed populace might have been able to stop the shooters themselves. This morning's Empire State Building shooting, though, points up the difficulty that even trained law enforcement professionals have in dealing with what they call an “active shooter scenario,” in a crowded public place.

Nine bystanders were injured in the firefight between two police officers and the suspect, Jeffrey Johnson. An unnamed law enforcement official told the New York Times that most or all of the injuries came from the 16 rounds police fired at Johnson. Johnson, detectives speculated to the Times, probably got off one shot at police.

“No matter how realistic their training is, it can never prepare an officer for a shooting,” says Dr. David Klinger, a former Los Angeles police officer and current criminology professor at the University of Missouri-St. Louis, who has interviewed hundreds of police officers involved in shootings. According to Klinger, the most effective training technique is what's known as “force on force” training, where officers are put into active shooter scenarios and use modified paint balls (“Simunition”) in their service weapons. Force on force training is a component of both the NYPD's recruit training, and re-training for active duty officers (all NYPD officers must go through firearms re-qualification twice a year). But it's essentially impossible for a police force of 35,000 officers facing constant budget crunches to completely train all of its members for every situation.

“There are professionals I work with who you would see that they're going to be able to stop a threat, will shoot the right number of bullets, and keep civilians as safe as possible,” says Klinger. “But unless this is something you train for on a daily or weekly basis, it's not something you can be truly prepared for.”

Even when officers do everything right, other officers and bystanders can be hit by bullets or bullet fragments that ricochet or pass through a suspect. With none of the nine Empire bystanders who were hit facing life-threatening wounds, there's a good chance that ricochets or pass-throughs accounted for many of the injuries.

According to Dave Smith, a retired police officer and lead instructor for law-enforcement training company Calibre Press, tactics for dealing with active shooters have changed significantly since the 1999 Colombine, Colorado school shootings. “The standard then was to form a secure perimeter around the scene before making a secure entry,” he says. But as police were doing that, people were being shot inside the school. “Now,” says Smith, “most officers are trained to engage a shooter more aggressively and stop the killing-clock as quickly as possible, even if that means risking their own lives.”

In the wake of the 2006 Sean Bell shooting, the NYPD commissioned a study of its firearms training and tactics by the RAND Corporation think-tank. The study was largely positive, but recommended some tactical changes, more individual training time for officers, and more advanced training facilities. According to RAND, there have been no follow-ups to see how the department has improved its training since the study was published in 2008.

Perhaps another study, of this particular shooting, and the tactics of the NYPD and other law enforcement agencies more generally, is in order. While the NYPD doesn't exactly have a stellar reputation for being open with the public and press, the department takes its shooting investigations very seriously, and has been remarkably forthcoming about the specifics of the Empire shooting thus far. But, cautions Smith, all the studies and training in the world can only go so far in helping police deal with such complicated shootings, where sometimes there are no good options.

“It's a cop's absolute worst nightmare, and it's only worse in a place like New York,” says Smith. “In almost every other city your backstop is cars and buildings, in New York City you have people.”

Those complications are something injured Empire bystander Robert Asika knows all too well. After being released from Bellevue Hospital, he told the New York Times that he was struck by a police bullet, and that he was “very lucky” that it passed cleanly through his right arm. Asked how he felt about being shot by police, and not the assailant, he said, “I guess, you know, stuff happens.”