Dave Sanders, the teacher who had directed students to safety in the cafeteria and elsewhere, was coming up the stairs and rounding a corner when he saw Klebold and Harris with guns raised. He quickly turned around and was about to turn a corner to safety when he was shot. Sanders managed to crawl to the corner and another teacher dragged Sanders into a classroom, where a group of students were already hiding. The students and the teacher spent the next few hours trying to keep Sanders alive.
Klebold and Harris spent the next three minutes indiscriminately shooting and throwing bombs in the hallway outside the library, where Sanders was shot. They threw two pipe bombs down the stairs into the cafeteria. Fifty-two students and four staff were hiding in the cafeteria and could hear the gunshots and explosions.
At 11:29, Klebold and Harris entered the library.
Klebold and Harris entered the library and shouted "Get up!" Then they asked for anyone wearing a white cap (jocks) to stand up. No one did. Klebold and Harris started firing; one student was injured from flying wood debris.
Walking through the library to the windows, Klebold shot and killed Kyle Velasquez, who was sitting at a computer desk rather than hiding under a table. Klebold and Harris set down their bags and started shooting out the windows toward policemen and escaping students. Klebold then took off his trench coat. One of the gunmen yelled "Yahoo!"
Klebold then turned and shot at three students hiding under a table, injuring all three. Harris turned and shot Steven Curnow and Kacey Reugsegger, killing Curnow. Harris then walked over to a table near him where two girls were hiding underneath. He banged two times on the top of the table and said, "Peek-a-boo!" Then he shot under the table, killing Cassie Bernall. The "kick" from the shot broke his nose.
Harris then asked Bree Pasquale, a student sitting on the floor, if she wanted to die. While pleading for her life, Harris was distracted when Klebold called him to another table because one of the students hiding underneath was black. Klebold grabbed Isaiah Shoels and started dragging him from under the table when Harris shot and killed Shoels. Then Klebold shot under the table and killed Michael Kechter.
Harris disappeared into the book stacks for a minute while Klebold went to the front of the library (near the entrance) and shot out a display cabinet. Then the two of them went on a shooting rampage in the library.
They walked by table after table, shooting non-stop. Injuring many, Klebold and Harris killed Lauren Townsend, John Tomlin, and Kelly Fleming.
Stopping to reload, Harris recognized someone hiding under the table. The student was an acquaintance of Klebold's. The student asked Klebold what he was doing. Klebold answered, "Oh, just killing people."3 Wondering if he too were going to be shot, the student asked Klebold if he was going to be killed. Klebold told the student to leave the library, which the student did.
Harris again shot under a table, injuring several and killing Daniel Mauser and Corey DePooter.
After randomly shooting off a couple more rounds, throwing a Molotov cocktail, taunting a few students, and throwing a chair, Klebold and Harris left the library. In the 7 1/2 minutes they were in the library, they had killed 10 people and injured 12 others. Thirty-four students escaped uninjured.
Back Into the Hall
Klebold and Harris spent about eight minutes walking down the halls, looking into the science classrooms, and making eye contact with some of the students, but they didn't try very hard to get into any of the rooms. Students stay huddled and hidden in many of the classrooms with the doors locked. But locks wouldn't have been much protection if the gunmen had really wanted to get in.
At 11:44, Klebold and Harris headed back downstairs and entered the cafeteria. Harris shot at one of the duffel bags they had placed earlier, trying to get the 20-pound propane bomb to explode, but it didn't. Klebold then went over to the same bag and began fiddling with it. Still there was no explosion. Klebold then stepped back and threw a bomb at the propane bomb. Only the thrown bomb exploded and it started a fire, which triggered the sprinkler system.
Klebold and Harris wandered around the school throwing bombs. They eventually went back to the cafeteria only to see that the propane bombs had not exploded and the sprinkler system had put out the fire. At exactly noon, the two went back upstairs.
They headed back to the library, where nearly all the uninjured students had escaped. Several of the staff remained hidden in cabinets and side rooms. From 12:02 to 12:05, Klebold and Harris shot out the windows toward the policemen and paramedics that were outside.
Sometime between 12:05 and 12:08, Klebold and Harris went to the south side of the library and shot themselves in the head, ending the Columbine massacre.