A man apparently despondent over the death of his sister fired a gun in the Fairfax Hospital parking lot late Wednesday night, then fired again in the emergency room foyer, sending scores of people diving for cover, Fairfax police said yesterday.

The man, identified as Michael J. Strickland, 32, of the 12000 block of Waterside View Drive, Reston, was arrested by police officers who were in the hospital. No one was injured.

Strickland, who is being held in the Fairfax jail in lieu of $2,500 bond, was charged with discharging a firearm in public, brandishing a firearm and reckless discharge of a firearm.

Hospital officials said Strickland's 21-year-old sister had been pronounced dead at the hospital about two hours before the shooting. His sister, identified as Kathleen P. Strickland, a senior at George Mason University, had collapsed that evening after lifting weights and running laps in the university's field house, Helen Ackerman, a university spokeswoman, said.

An autopsy was being conducted.

Hospital officials said yesterday that the hospital, which houses Northern Virginia's only trauma center -- an emergency room with staff and equipment trained to deal with the most serious injuries -- is accustomed to dealing daily with physical and verbal abuse of its emergency room staff by people entering the trauma unit. However, they said Wednesday night was the first time they had encountered someone shooting.

Carol Miller, director of the emergency department at Fairfax Hospital, said she was impressed with how well the hospital staff responded within the few seconds of hearing the shots in the parking lot.

Miller said a nurse heard the shots and saw the man walking toward the hospital. "He came into the foyer area . . . . He lifted the gun up and began to point it at the ceiling," Miller said.

Miller said the nurse, who was working on a dialysis patient, carried the patient into a back room as other staff members cleared the main hallway pushing patients into side rooms and locking doors. Other employees ran into bathrooms to get out of the way.

Miller said by the time the man walked into the emergency room, about 25 other people who were in the waiting room were on the floor. The man, who was silent, pointed his gun and did a sweep of the lobby, "as though he was looking at something to shoot at," Miller said. "He looked like he was looking for somebody. {The gun} was raised but he never pointed at anything directly."

"Everbody was down off their chairs," she said. "The man turned around and started back where he came from . . . retracing his footsteps when Fairfax County police told him to freeze and drop his weapon. They had their guns drawn. He knelt down on the floor, dropped his weapon and they arrested him."

Miller said a Fairfax police officer is on duty at the hospital all night, in addition to the hospital's own security staff. She said at the time of the incident three other police officers were in the lobby area as well as two George Mason University campus police officers who had come in earlier with the man's sister.