Dr. Christina Catlett was working in the emergency room at Johns Hopkins Hospital when word came of a shooting just floors above. Paul Warren Pardus had killed his mother, shot her physician and then taken his own life.
The facility quickly locked down amid fears that the shooter was still active, but Catlett and her colleagues went right back to work on their patients, now among them wounded colleague David B. Cohen.
"My first concern was for my patients and staff," Catlett said.
Law enforcement officials say people confronted with public violence must decide whether to run, hide or fight. But at a national symposium hosted Friday by Hopkins, experts said the 2010 Baltimore incident raised important questions about how medical professionals can stay safe as they care for vulnerable patients.
Dr. Gabor D. Kelen, who heads the department of emergency medicine and serves as the director of Hopkins' Office of Critical Event Preparedness and Response, said in an interview that there is no centralized set of guidelines for hospitals. He hopes to create a reference for others to follow.
"What should I, as an individual do, if I feel someone on my floor has a gun? … We've had it in the back in our minds. What if this really does happen, what am I supposed to do?" he said. "We're cautiously optimistic that we will find some reasonable, meaningful steps to take to the staff."
Hospitals, like other public places, are trying to reconcile how to improve security while maintaining an open, welcoming environment.
In addition, symposium participants said, institutions face increasing concerns over liability for what happens on their property, but are limited in their ability to restrict firearms because of constitutional concerns.
James G. Hodge Jr., a professor at the Sandra Day O'Connor College of Law at Arizona State University and a conference participant, said that "hospitals are really vulnerable right now." They tend to have less security than courthouses and other public places. "In a setting where emotions are running high, these events are predictable," he said.
Hospitals around the country have dealt with violent incidents. In Long Beach, Calif., a hospital pharmacy employee killed two colleagues in 2009. An Akron, Ohio, man fatally shot his wife in a hospital in what authorities described as a "mercy killing" in 2012, according to news reports.
And just last month, a man took his own life inside the lobby of a New Jersey hospital emergency room.
Kelen said the Johns Hopkins shooting in September 2010 "really got us thinking in a very serious way."
"Hopkins did have a plan. Hopkins did execute it," he said. "This was a normal guy who had been visiting his mother and all of a sudden had gone off. It wasn't easy to recognize."
Shortly after the shooting, Kelen, Catlett and two other researchers studied hospital shootings and found that they are rare occurrences and that most "involve a determined shooter against a specific target."
Kelen said high-tech security devices are not very effective, given the amount of medical equipment — such as wheelchairs — that must pass through hospital entrances. Also, he said, it is impractical to screen critically injured or seriously ill people who need urgent treatment.
Hodge said hospital officials are still looking for better ways to vet patients and other visitors.
Medical facilities are increasingly held responsible under "premises liability," he said, under which plaintiffs can win civil awards because of hazardous conditions. Premises liability is no longer restricted to the physical condition of the property, but whether violence can be prevented there, Hodge said.
It can be difficult to restrict guns entirely, he added. For instance, Hodge mentioned that Florida failed adopt a measure prohibiting guns at public hospitals because of Second Amendment concerns.
Other facilities now require training for staff, including nonsecurity personnel, while some in New York City and Detroit have installed metal detectors, and others have reduced the number of public entrances and hired additional security, creating environments similar to federal office buildings, he said.
One veterans hospital in Portland, Ore. is screening patients and visitors, he said, looking for potential psychiatric concerns in hopes of heading off danger.