Stepping Stone

Voight makes a significant tactical error after the shots are fired, albeit a common one TV cops make. In a shots fired situation, officers such as the ones in the patrol car would be deployed to the rear of the building to prevent the escape of the occupant(s). Instead, all of the officers congregate at the front of the building. A similar error is made later on at the apartment building, which results in a vehicle pursuit.

References Chicago Fire (2012)