Season 6, Episode 15 - Air Date: 2/18/2010
In his new role as Chief, Derek restores the hospital lecture series, and Richard, Bailey and Callie present to the group pivotal surgical cases from their pasts – Bailey reflects on her first days as a shy resident, Callie looks back on a polio case, and Richard recalls a case in which he and Ellis worked on a patient diagnosed with GRID, a disease later called AIDS.