Now to the deadly shootout at a Pennsylvania hospital that left one person dead and a doctor wounded. Bringing it to an end was the quick thinking of a doctor and ABC's Ron Claiborne is outside the... See More
Now to the deadly shootout at a Pennsylvania hospital that left one person dead and a doctor wounded. Bringing it to an end was the quick thinking of a doctor and ABC's Ron Claiborne is outside the hospital in Darby, Pennsylvania, with the latest. Good morning, Ron. Reporter: Good morning to you, robin. Quick thinking and armed. Authorities say what happened here is that a psychiatric patient with a criminal past got into an argument with his caseworker, opened fire on her allegedly and then the doctor pulled out his gun and shot the gunman. This morning, new details about the shootout that put Pennsylvania's mercy Fitzgerald hospital on lockdown and left one person dead. You don't expect this to happen. Reporter: It was just after 2:00 P.M. Thursday when police say Richard Plotts seen here in an old photograph made his way to the psychiatric floor of mercy Fitzgerald's wellness center with his caseworker, 53-year-old Teresa hunt. The two entered the office of psychiatrist Dr. Lee Silverman for a routine appointment. Soon witnesses heard loud arguing inside and they opened the door and saw Plotts pointing a gun at Dr. Silverman and reportedly called 911 but it's too late. By 2:30 shots fired. I'm scared. Because I'm really scared. Shook me up. Reporter: Dr. Silverman tells prosecutors Plotts shot and killed hunt, the caseworker. That's when the doctor said he dove behind his desk and pulled out his own gun firing back. The extent of the amount of bullets that were fired between the perpetrator and the doctor is unclear. Reporter: During the gunfight a bullet grazes Dr. Silverman's head and Plotts is shot twice in the stomach but survives. Prosecutors say it all comes to an end when the struggle spills out into the hallway and another doctor and caseworker tackle Plotts. This morning, it is unclear why Dr. Silverman brought a gun to work which is against hospital policy. But police say Plotts may have done more harm had Dr. Silverman not intervened. This morning, Plotts remains in critical condition and as for Dr. Silverman, authorities say it is legal in this state for him to have a gun and he will not be, robin, the subject of a criminal investigation in this matter.
This transcript has been automatically generated and may not be 100% accurate.