ER: Season 12, Episode 22

12 - 22: Twenty-One Guns

A seemingly ordinary day with the usual collection of patients turns anything but when two prisoners intent on escape come to the ER for treatment. Aided by a conspirator posing as a patient, their desperate actions place a doctor in harm's way and force a nurse to become a tool in their plan. Soon, gunshots ring out, another doctor hits the floor, and a staff member's life is in jeopardy.