Mike Bilben was coming out of the parking garage about 1:45 p.m. on O'Hara Street, across the street from Western Psychiatric Institute and Clinic of UPMC, when he heard three shots: bang, bang, bang.
Inside the clinic, a medical records technician who declined to give her name heard the same three bangs. She thought someone was loudly knocking on the door, until two people rushed into the office, screaming and crying that people had been shot. They locked the door and huddled there.
Outside, Mr. Bilben watched as a University of Pittsburgh police officer rushed in, followed shortly by dozens more police. They screamed at him and others in the garage to get back.
"They said they couldn't find the shooter and they said everybody had to leave," he said.
Across this section of Oakland, a sprawling complex of hospital and university buildings, fear and confusion reigned as word of the shootings spread. Some buildings were evacuated, but many people were told to stay put, to lock their doors and to stay away from windows.
Not long after 2 p.m., DeSoto Street was choked with police and emergency vehicles. Bystanders, many of whom had been alerted to the shootings by a campuswide email and text message, watched as officers in fatigues pulled long guns out of their trunks and rushed up the hill.
At UPMC Presbyterian, employees braced themselves for an onslaught of patients, some of whom were carried out of Western Psych on stretchers and walked by paramedics to the entrance of the hospital. But employees elsewhere in the hospital, all of whom declined to give their names because of a hospital policy prohibiting them from talking to the media, said they didn't hear of a lockdown and knew few details about the shooting.
In the University of Pittsburgh's Parran Hall, restless and curious faculty, employees and students hunkered down in the lobby, where they traded news and rumors. On the television screens in the hallway, a message flashed that the building was on lockdown and warned people to stay away from windows.
Doors to the nearby Petersen Events Center also were closed, with security warning people that no one could come or go without permission from the police. Inside, middle and high school students participating in a robotics competition munched on food from Burger King and Pasta Plus, gazing through the large glass windows as police leapt out of SWAT vehicles.
A woman with them licked ice cream from a cone while two men sat quietly on the wet steps outside, anxiously awaiting word on a friend who works inside the institute.
In Crabtree Hall, across the street from the clinic, staff were warned over a loudspeaker to stay away from the windows that faced the clinic and were moved away from offices on that side of the building. Donald Burke, dean of the School of Public Health, went to offices that had been declared off-limits, sternly ordering people away.
Rona de la Vega, a 27-year-old lab technician who works in Crabtree Hall just down Cardiac Hill from the psychiatric institute, said her mother, Teresita de la Vega, and nearly 2-year-old nephew, Kai, came to visit her shortly before the shooting.
They ran into a stairwell, where they tried to watch the action unfold until they were escorted away and told to find another place in the building to stay until the lockdown was lifted, which they estimated happened at about 4:30 or 4:45 p.m.
"I was always surprised nothing like this happened [before], because it's Western Psychiatric," Rona de la Vega said.
"It can happen anywhere," her mother added.
The women left Crabtree Hall before police reopened the area surrounding the institute, meaning Teresita's car was still parked behind police tape and they would have to search for a bus back to the South Hills, where they live.
In the nearby School of Medicine, staff were told to lock themselves in their offices.
"It was a little scary knowing it was across the street," said Kathy Scott, an evaluation coordinator with the school.
Eric Majeski, a pizza shop manager, rushed to the scene after getting a panicked phone call from his girlfriend, a cafeteria worker who delivers food to Western Psych. She hung up the phone abruptly as police moved her from the building, he said.
"She said a bunch of people had been shot," he said. "She had seen blood."
Mr. Bilben and others in the parking garage were told by police to shimmy out along the garage's concrete walls. The technician in the clinic and her work mates were evacuated about 90 minutes after the shooting started, when a police officer fetched them from the locked office and escorted them out.
At around 3:45 p.m., police on O'Hara Street casually meandered near the entrance of the building, though the scene remained very much active. Police escorted out staff members, some of whom clutched their faces in grief, walking them down the hill towards Fifth Avenue.
A group of young patients, including small children, were evacuated at about the same time. Many of the children were carried out in the arms of employees. Others walked tentatively down the rain-slicked steps in stocking feet. The group was loaded into the back of a large armored SWAT vehicle and driven away.
Members of the SWAT team escorted some nurses and other workers from the clinic to the University of Pittsburgh School of Medicine's Scaife Hall, where some people were given cookies hours after the shooting. In the nearby Biomedical Science Tower, one woman sneaked out a stairwell but found she probably wouldn't be able to return to the building after a smoke break.
Students at the Pittsburgh Science and Technology Academy 6-12 left school late that day, some gathering on the corner of Fifth Avenue and Thackeray Street for their parents to pick them up or so they could catch a bus.
Students stayed in their fourth-period classes, which they said began around 12:30, until they were dismissed about five hours later. Staff members brought them potato chips while some teachers played music or popular YouTube videos. Many said they learned about the shooting via online news reports or social media.
Karen Hough, a 55-year-old researcher who works in Pitt's Biomedical Science Tower One, said she learned of the shooting from a relative who works in a nearby command center.
Ms. Hough said she and her co-workers went through their day as normally as possible.
Ms. Hough said she felt safe in her building because people can only access most parts of it with an ID card. Even then, she said, the cards are programmed so that workers only have access to the floors where their work is based, meaning few people can access the entire building.
"It just doesn't surprise me," she said. "I know there are a lot of places you could run and hide here and no one would know."