Which of the following is explicitly prohibited when operating within the SDZ?

When operating within the Surface Danger Zone (SDZ), ensuring safety is the priority. Unauthorized personnel in the area is explicitly prohibited because their presence increases the risk of accidents and compromises the overall safety of the operation. The SDZ is designed to delineate areas in which safety hazards may exist due to the use of firearms and ordnance. Allowing unauthorized personnel could lead to serious injuries, as they may not be aware of the safety protocols or may not be equipped to respond to emergencies appropriately.

While the other choices also present safety concerns, the prohibition of unauthorized personnel is specifically highlighted within most safety regulations governing range operations. The use of non-standard ammunition and placement of targets near exit roads could indeed lead to unsafe conditions, but they stem from a different regulatory context that often intersects with broader range safety guidelines rather than being a primary focus of the SDZ itself. Thus, the explicit focus on keeping unauthorized personnel out is of paramount importance within the SDZ.