The most visible defensive shootings are by police.
In the past, a Richmond police officer might not have felt free to admit any traumatic effects from shooting someone in the line of duty. Few would willingly talk to a psychologist or psychiatrist about a shooting.
Now, city police don't have a choice, because Dr. Jon H. Moss will be at the scene before they leave.
"I help people deal with normal reactions to an abnormal event," said Moss, a private psychologist who works under contract with police, fire and ambulance workers in Richmond, sheriff's deputies in Hanover County and police in Ashland.
While some officers walk away from a shooting without emotional aftershocks, most struggle with the consequences of pulling the trigger on another human being, he said.
"It's not a day in the park. It has an impact on their lives," Moss said.
Some police officers will be angry at the person they shot for putting them in that position. Some will feel frightened. Some will get sick to their stomachs. Some will feel remorse. Some will question whether they have violated a basic tenet of their religious faith by killing someone.
"Everything being completely legal, justifiable and defensible, it still eats at you inside," said Hanover Sheriff Stuart V. Cook, who spent 25 years on Richmond's police force before moving to the county 12 years ago. "You never feel good about it."
And some just don't get over it. Moss knows of three Richmond police officers who eventually left the force and the profession after shooting someone in the line of duty. "Their lives changed," he said.
Capt. Mark K. Segal was 29 when, in a span of a few seconds, his view of life and police work changed. He had been a Richmond police officer for six years but never had used his gun against another person.
He was working as a detective on Sept. 13, 1989, when a robber took a motel clerk hostage in South Richmond and forced her to drive him south on Interstate 95. Segal and another officer caught up with them near Willis Road in Chesterfield County and forced them off the road.
Instead of running, the robber put his gun to the clerk's head and threatened to kill her. Segal had his gun trained on the man's chest, waiting for him to loosen his grip on the woman. The man turned his weapon on Segal, who fired three times through the windshield. The man tried to pull the woman back to him and Segal fired three more times, hitting him twice. The man, 20-year-old Darryl L. Webb, survived and went to prison.
"It's amazing how those few seconds will have an impact for the rest of my life," said Segal, who now is in charge of records and technology for the police force.
He received a gold medal of valor for his conduct. His actions were featured on national television. He was a hero.
But Segal remembers not being able to sleep for days after the shooting. He remembers having flashbacks and an upset stomach. Watching bullets hit another person, fearing what that person might do in a desperate burst of adrenaline - it is not a normal experience being on the other side of the gun.
"It eats you," he said. "It really eats you up."
Segal said the experience also matured him as a person and a policeman. "Over the course of 13 years, really a day doesn't go by that in some way I don't think about that incident or the gravity of what we do.
"It's not that the fun ended, but the seriousness really sank in."