When Dr. Spencer Reid risked his own life to save a killer.
When the team was called to Texas to catch a spree killer that was murdering classmates that bullied him and his girlfriend, the case really resonated with Reid. Spencer, who had been ruthlessly abused in high school, lied to the rest of the team in order to get to the boy before they did so that he could convince him to turn himself in. Because of the small-nature of the town, the boy had decided that he would rather commit suicide by cop than turn himself in, but Reid promised him that he would protect him.
Spencer kept his promise, evening standing between his own team and the boy in order to prevent them from shooting him.
Season 3, Episode 16 “Elephant’s Memory”