The Crossing

S7, E15: In the series' 150th episode, a massive train wreck mobilizes the emergency room doctors. Corday, Carter and Kovac rush to the scene. Corday falls and injures her back, bringing on contractions in only her 25th week of pregnancy. While amputating the legs of a fallen firefighter, Corday stops because of her pain. She accompanies an injured boy and rides back to the hospital in a helicopter. Meanwhile, Carter finished the amputations. Abby helps the contractions safely subside. The bishop helps Kovac reconcile with his past before the bishop dies.