American teachers will be provided with a simulation to help them protect children in the event of a gunman entering a school. Since 2000, nearly one-third of mass shootings involved a school according to the FBI. This simulation has been created by Homeland Security and the US Army to help save lives. It allows users to see through the eyes of a teacher, pupil, police officer or gunman. This technology has previously been used to prepare soldiers for a war situation. The simulation can analyse what factors effect outcomes such as automatic closing doors. Report by Adam Page.