He shot the professor, Christopher James Bishop, in the head. Students screamed and hid under desks; Cho kept shooting. He said nothing. He did not appear to be looking for anyone in particular. He just fired and fired again.
In Room 204, professor Liviu Librescu was lecturing on engineering when the first shoots rang out. He ran to the door and held it shut. Students tried to take cover, but as the gunfire got louder, they tugged open the windows and jumped.
Bang. Bang. Time seemed to stop. Each sound was isolated, and each image. Students lying on the floor, pressing their feet against a classroom door to hold it closed as bullets flew above their heads. The chipped wood of a lectern hit by a bullet. Scattered notebooks. A tourniquet made from a torn sweatshirt.
Gene Cole, a custodian, was walking through the second floor in search of a co-worker when he saw a student lying in the corridor, wounded but struggling to get up. "There was blood all over the floor," he said.
Cho approached, firing, and Cole fled downstairs.
At 9:45 a.m., police responded to a 911 call from Norris Hall. They found the front doors blockaded. A second e-mail went out to students and staff: "A gunman is loose on campus. Stay in buildings until further notice. Stay away from all windows."
Police began blaring warnings over loudspeakers: This is an emergency. Take shelter. Resident advisors went door to door in the dorms, pounding on walls, yelling at students to stay in their rooms -- or in some cases, to come down to a common area where they could all wait out the lockdown together.
"I was in shock," said Janesa Wright, 18. "I thought I heard it wrong."
Freshman Erin Kennedy said she, too, was unable to take it in: "I didn't want to believe it was my school."
The scene outside Norris was chaotic. Within moments of arriving, heavily armed officers had broken through the chained doors and stormed up the stairs, following the sound of gunshots. Law enforcement personnel lined the street outside, carrying rifles and assault weapons.
They screamed at any student who wandered close: "Get back! Get back!"
But from outside, the terror was not obvious. Chris Hinkle, 18, heard the bang-bang-bang and assumed the noise had something to do with the construction work going on nearby. "Nobody," he said, "was as worried as they should've been."
