Running late for class, Drew Jeskey entered Cole Hall just minutes before instructor Joseph Peterson began his lesson Thursday.
Jeskey normally sits in the middle of the lecture room, but because of the time, he slid into the last row, about 65 feet from the stage. An hour passed, and Jeskey began skimming through his notes. Then, the exit door to the right of the stage swung open.
"Everyone sort of looked up and stared at the guy," Jeskey said. "It seemed like a joke at first. We'd never seen that door open before. You didn't see the gun right away. It was right next to his leg.
"The first shot, I didn't think it was real. Then he shot at the teacher. Right there, I knew it was real."
Jeskey, a junior midfielder-defender for the Northern Illinois men's soccer team, was among the dozens of students facing a chilling reality Thursday in DeKalb, Ill. Former NIU student Steven Kazmierczak opened fire in a geology class, killing five and wounding 16 others before turning the gun on himself.
After the first shot, which Jeskey calls "the loudest thing I've ever heard," students began scrambling to get out of the room. Jeskey fell to the floor, banging his knee and hand, and slipped several times as he crawled the 20 or so feet to the door.
"When I had my back turned to [Kazmierczak], I heard two more shots as I was trying to get out," he said. "Then, when I was outside, I heard another one. First reaction was to just get out of that place."
Tim Mayerbock was on his way to a psychology class, taking his normal route past the front entrance of Cole Hall, when two blasts rang out.
Mayerbock froze. He recognized the noise, but couldn't figure out why he was hearing it now, in the middle of a college campus on Valentine's Day.
"I'm a big hunter," Mayerbock said, "so I know what a shotgun sounds like. From the second it started, I was pretty aware of what was going on.
"Even though it seemed inconceivable, it was definitely real."
Mayerbock, an offensive guard for NIU's football team, heard the initial shots, then a flurry.
"It was almost rapid fire," Mayerbock said. "It was one shot after another. People were just running out screaming. A couple seconds later, I saw someone fall to the ground coming out the door, obviously got shot in the leg."
The victim was Troy Chamberlain, a freshman Mayerbock had never met. Chamberlain had been shot in both legs, leaving him with 22 buckshot pellets in his left thigh and three in his right thigh.
Mayerbock ran to Chamberlain. When he approached the bleeding student, Mayerbock got a glimpse inside the lecture hall.
"I looked down the hallway and saw this guy with a gun," Mayerbock said. "My reaction was he was going to come and finish people off. I thought he was coming after this kid.
"I just grabbed the kid and took off as fast as I could."
In nearby DuSable Hall, Britt Davis had left his communications lab after someone informed him of the shooting. Trying to get his cell phone to work, Davis saw a crowd huddled around a bleeding student wearing a letterman's jacket.
"I thought he was an athlete," said Davis, a wide receiver on the football team. "Then I noticed Tim."
The thing I've been hung up on the last couple days is how could someone do this? What has to be going on in a person's mind to be able to do this to
Mayerbock had helped Chamberlain to safety and was using his Huskies jacket to keep the freshman warm.
"I am very grateful that Tim was there at that moment because I do not know if I could have made it all the way to DuSable Hall without the help from him," Chamberlain wrote in an e-mail to ESPN.com. "My legs were beginning to go out from the shotgun wounds and he was there to help support me."
Davis quickly joined the group helping Chamberlain.
"Everybody was on the same page, just talking to him, keeping him as calm as possible, keeping him from going into shock until the paramedics got there," Davis said. "He was communicating back to us. He was fighting it."
Despite having no first aid training, Mayerbock found a towel and applied it to Chamberlain's wound. He also phoned for an ambulance.
When paramedics arrived, Mayerbock accompanied Chamberlain to Kishwaukee Community Hospital, which treated most of the shooting victims.
"I basically wanted to wait until I could talk to Troy," Mayerbock said. "I was sitting there in the waiting room and seeing parents and friends and families running in crying, screaming for their kids.
"The thing I've been hung up on the last couple days is how could someone do this? What has to be going on in a person's mind to be able to do this to someone?"
After escaping Cole Hall, Jeskey immediately dialed 911. As he ran, Jeskey saw a student running with buckshot shells in his neck.
"I just kept saying, 'There's a shooting going on at Cole Hall,'" Jeskey said. "As I was running, I was talking at the same time. And it was windy, so the operator actually thought I was saying that I was the shooter."
Shortly after the shooting, Jeskey text-messaged his sister, Katie, a fellow NIU student, to let her know he was OK. But hours passed before most loved ones could be reached.
Mayerbock received about 20 calls from his coaches while he was at the hospital, and several soccer coaches came to Jeskey's apartment after learning he had been in the classroom.
"My cell phone wasn't working for hours," Davis said, "I just went home and watched the news, basically praying for everybody. You never think that something like this would happen."
After learning Chamberlain would be OK, Mayerbock left the hospital and went home. He couldn't sleep Thursday night and had several interviews with police Friday morning before "falling asleep from pure exhaustion."
Jeskey hasn't had trouble sleeping since Thursday, but the terrifying scene remains fresh in his mind. Although he didn't know the victims, his father, Dave, was in the same NIU fraternity as the father of Dan Parmenter, one of the five students killed.
"The sound and the flash of the gun is unforgettable," Jeskey said. "Just now it's sinking in."
With all classes and athletic events canceled until Feb. 25, Jeskey spent the weekend going back and forth between DeKalb and his home in St. Charles. Mayerbock went home to Chicago on Friday and returned to campus Monday afternoon.
The football team is scheduled to meet Tuesday, and men's soccer assistant coach Eric Luzzi hosted several players for dinner Monday night. The men's basketball team will reconvene Wednesday for practice.
"Certainly, this is a time where our university and community has banded together," basketball coach Ricardo Patton said. "In all sports, the players really bond and become closer to each other. Now they will probably feel a greater sense of family after this tragedy."
Mayerbock plans to spend the week in the weight room, trying not to think about the shooting. He turned off his cell phone for much of the weekend, though he has communicated with Chamberlain through text messages and on Facebook.com.
"He was telling me that he doesn't know if he'd be dead right now or what," Mayerbock said. "I'm happy I was able to help somebody else, but then again, you just wonder what more could have been done. Was there somebody else laying right by a door?
"That's something that's hard to deal with."
Chamberlain doesn't discount what Mayerbock did that day.
"It meant a lot," Chamberlain wrote. "This was the first time I had met Tim or even seen him. I do not know many people that would have put their life in harm's way to help a total stranger out. It really showed how genuine and a caring person that he is."
Adam Rittenberg is a college football writer for ESPN.com. You can contact him at email@example.com.