S11, E22: On Carter's final shift at County General, four new interns begin their medical careers. After completing their rounds, Carter, Kovac and most of the emergency room staff attend Carter's surprise going-away party. Ray leaves to go to another event where the revelry is interrupted by a disaster that truly tests his triage abilities. The casualties are taken immediately to the hospital where a skeleton staff, headed by Abby and Neela, must overcome their lack of experience and treat the patients. Meanwhile, Pratt finally gets the courage to confront his father, Charlie (recurring guest star Danny Glover - "Lethal Weapon" films, "The Royal Tenenbaums"). And Sam and Kovac search for Sam's son after he runs away in search of his imprisoned father.