Kirklin was exiting through the west exit of Columbine high school with two friends Daniel Rohrbough and Sean Graves, both aged 15 on their way to Smoker's Pit (Leewood Park) across the road from the school where the smokers would go. Two students in black trench coats Eric Harris and Dylan Klebold walked up to them and at about 12 feet away, began firing at Kirklin and his friends. First hit was Rohrbough killing him instantly. Kirklin tried catching him as he fell but was shot in the foot, right leg and chest himself. Graves was shot at but was able to make it to the cafeteria entrance before getting shot again in the back, paralyzing his lower body.
A short while later Klebold shot Kirklin at point black range in the side of his face.
Sean Graves has stated shortly after the incident that he and Kirklin haven't spoken much about it, saying he gets too emotional to talk to Lance in person.