This paper looks at current active shooter mitigation techniques employed by schools throughout the country in an attempt to mitigate casualties during an active shooter event. The researchers modified an existing Columbine High School agent-based model created by Jae Lee, MS, to examine if the introduction of a school resource officer (SRO), concealed carry weapon (CCW) holder, or both would change the outcome of the previous research. RUN.HIDE.FIGHT® scenarios were modeled with the same parameters of the previous work, but now included armed first responders during the incident to assess whether their presence decreased casualties through a reduction in response time. The researchers determined that the addition of either an SRO, CCW holder, or both significantly reduced casualty rates during an active shooter scenario.