Focusing on training programs designed to help police officers enter into hostile situations while remaining safe, this article describes the San Diego Police Department’s active shooter response program. Although most law enforcement agencies are highly conservative in regards to officer-suspect confrontations, the events at Columbine High School on April 20, 1999, in Denver, Colorado demonstrate the importance of police departments taking quick action when innocent bystanders and hostage's lives are at stake. This article details the San Diego Police Department’s in-services training division program designed to teach field responses to active shooter situations. After arguing that police officers’ success or failure at an active shooter incident is determined by advanced planning, the author highlights the importance of contact team officers who align themselves in tactically sound formations in order to move towards shooters or towards the sound of gunfire. Following descriptions of various tactical formations and movements, dependent on different criminal situations, the article describes the training of rescue and containment teams to aid the victims of active shooter incidents. Highlighting the importance of rescue teams being ready and able to do battle and remain flexible, the author concludes that police officers need to remember that stopping the suspects is always the primary goal of any active shooter mission.