Senior Kevin Sterne is carried out of Norris Hall after the rampage. Sterne kept his cool, applied a tourniquet to stop bleeding and lived. Alan Kim | Roanoke (Va.) Times

As a child, he had survived the Holocaust. As an adult, he had survived persecution for defying Romania's brutal communist regime during the Cold War. At last, with their children grown, he and his wife, Marlena, seemed to have found a safe haven on a quiet university campus in rural Virginia.

But Monday, trouble found him once more. With bursts of gunfire rattling through the second floor of Norris Hall, Librescu, 76, closed his classroom door and urged his students to escape out the windows, recalled senior Caroline Merrey of Baltimore, the third student to jump.

As they fled, Librescu held the door shut with his body as the gunman, Cho Seung-Hui, tried to force his way in.

Moments after the last student leapt to safety, Cho apparently succeeded in opening the door and shot Librescu to death.

"My father has showed a sense of his courage in standing up for what he believed since long ago," said Joe Librescu, the professor's son.

What Liviu Librescu did was the most conspicuous act of heroism to surface thus far in the massacre, but it was not the only story of bravery.

There were many reports of students using clothing to fashion tourniquets to stop bleeding from gunshot wounds, or take other first-aid measures.

Doctors say Kevin Sterne is alive and in stable condition because of his quick thinking.

Sterne is a former Eagle Scout who kept enough cool to fashion a tourniquet from an electrical cord after a bullet tore an inch-long gash through the femoral artery of his right leg.

"The patient that I took care of was an incredible guy," said Dr. David Stoeckle, chief of surgery at Montgomery Regional Hospital. "He was bleeding significantly ... he knew he was bleeding to death."

Derek O'Dell, a 20-year-old sophomore majoring in biological sciences, said the gunman entered his German class and opened fire without saying a word. O'Dell said most of the approximately 20 students in the class were hit. A bullet struck him in the right arm.

Cho left the room, and O'Dell and another student, who was not identified, slammed the door and held it shut with their feet. Minutes later, Cho reportedly returned and tried to push his way back into the classroom.

"He got the door open maybe an inch or two, and then we were able to shut it again," O'Dell said.

Another student who kept Cho at bay was Zach Petkewicz: "I was completely scared out of my mind originally and just went into a cowering position," Petkewicz told CNN in describing his initial response. "And then I just realized, I mean, you've got to do something."

Petkewicz said he and his 10 classmates became aware of the danger when they heard gunshots and a scream. One student, peaking out the door, glimpsed the gunman and ducked back inside.

"Everybody kind of went into a frenzy, a panic. I hid behind the podium and then just kind of looked up at the door. It was just, like, there was nothing stopping this guy from just coming in," he told CNN.

"And so I said, 'We need to barricade this door.' Me and two others got up, threw a couple of tables in front of it, and had to physically hold it there. ... He came to our door, tried the handle, couldn't get in, because we were pushing up against it.

"He tried to force his way in, got the door to open up about six inches, and then we just lunged at it and closed it back up. And that's when he backed up and shot twice into the middle of the door," Petkewicz said.