Locking down the Virginia Tech campus would be akin to shutting down a small city - and even then, there's no guarantee that a student concealing weapons couldn't find a way in, campus security experts said.
"In this situation, the shooter was a legitimate student who had an ID card," said Robert Rowan, director of the emergency response team at the University of Maryland, Baltimore. "You could easily lock a building with the shooter in it. I'm not sure that would have prevented the situation there."
Virginia Tech officials continued to face questions yesterday about their response to the initial report of a shooting Monday. After two people were shot in a dormitory, more than two hours passed before students received alerts through e-mail that a gunman was on the loose.
Campus officials have defended their response, saying they locked down the dormitory and sounded sirens. They attributed the delay in sending out the mass e-mails to their conclusion that the first deaths were part of a domestic dispute and the danger to others had passed, even if the killer was still on the loose.
Officials from other universities and Virginia Tech students offered mixed assessments yesterday of the university's handling of the shootings - especially of the decision by campus officials to consider the danger past when the first two bodies were found.
Susan Riseling, chief of campus police at the University of Wisconsin-Madison, said a lockdown would entail securing hundreds of buildings.
"The concept of a lockdown on a 2,600-acre campus that is open and has a thousand entry points by foot or hundreds by car is not feasible," Riseling said.
Riseling, who also serves as vice president of the International Association of Chiefs of Police, said that locking campus buildings could prove dangerous if the shooter is outside and people are prevented from taking cover indoors.
She also said that sending out alerts by e-mail can take longer than people might expect. First, officials must respond to the call and learn the details of the crime. Then they must weigh the threat to the community and consider whether sending out alerts, through e-mail or reverse 911 calls, for example, would stir unnecessary panic.
She pointed out the rarity of someone killing a person he knew - a "domestic" shooting - and then killing people at random.
Joanna M. Rubard, 21, a Virginia Tech junior from Herndon, Va., wondered whether lives could have been saved if students had been alerted sooner to the first shooting.
She said she did not understand why the university did not immediately institute a lockdown.
"Three hours later I had no idea," about the shooting, she said. "No one had any idea what was going on. Maybe that would have prevented the shooting at Norris [Hall] if the campus had been alerted."
Virginia Secretary of Public Safety John Marshall called the university's response a "coordinated, prompt and professional" one.
Rea Ohlschlager, 21, of Lynchburg, Va., said she was disappointed by the lack of communication between the university and students during the time the gunman was on the loose.
"Getting word out that there was a problem - that was my main criticism," she said. "It was kind of upsetting how long it took for them to tell us."
But Ohlschlager, like many other students interviewed, did not fault campus authorities for failing to lock campus buildings during the pursuit of the shooter.
"It's an open campus," she said. "All open campuses leave buildings unlocked. It's always been that way."
Brian Thomas, a freshman from Columbus, Ohio, said school officials could not be blamed for how they responded to the shootings. "Even though this happened, I still feel this is a very safe campus. This thing, it's not something you can prevent or plan for," he said.
The hypothetical scenario has gone through Cleveland A. Barnes' mind more than once in the past 24 hours: Someone has been fatally shot on the University of Maryland's Baltimore campus. The gunman is loose. And Barnes, chief of the university police, must decide whether to shut down the 36-acre campus in the city's downtown.
The campus has more than 10,000 visitors a day, officials point out, including many patients of the university's medical facilities. But if a shooter were on the loose, Barnes said he would likely order all campus buildings to be locked and cordon off the area, and then call Rowan, the emergency response director, to notify him of the situation.
"Time is of the essence," Barnes said. "If you don't respond quickly, basically what you're doing is you're only allowing the shooter additional opportunities to, one, shoot other individuals, and two, you allow him freedom of movement."
Rowan said if he received such a call from Barnes, he would send out e-mail alerts to students and automated phone calls to security guards at each of the campus buildings within 10 to 15 minutes.
"Assuming that the shooter was not captured, or we didn't know where it was, we would probably go into our 'shelter in place' plan," he said. Under the plan, students would be told by guards and through e-mail to stay indoors until notified.
Jacob Rimer, security chief for Hebrew University in Jerusalem, where visitors must pass security checkpoints before entering the campus, said the shootings at Virginia Tech testify to the need for all college campuses to be protected by checkpoints.
"It's not only because of terrorism, it's also because some people are crazy," he said.