Lépine moved out of his mother's home into his own apartment, and in 1986 he applied to study engineering at École Polytechnique de Montréal. He was admitted on the condition that he complete two compulsory courses, including one in solution chemistry. In 1987, Lépine was fired from his job at the hospital for aggressive behaviour, as well as disrespect of superiors, and carelessness in his work. He was enraged at his dismissal, and at the time described a plan to commit a murderous rampage and then commit suicide. His friends noted that he was unpredictable, flying into rages when frustrated.