Fire teams work out their bugs using the Doom simulation so they can operate at close to full speed in the field, which improves range use efficiency. A typical site exercise begins with four marines sitting at computer terminals that are networked together. They receive a text file frag order that specifies the training objectives and that covers the potential enemy and friendly units. The goal, according to 1st Lt. Scott A. Barnett, USMC, Marine Doom project officer, is not simply to run around and shoot at anything that moves. Participants have a specific objective to accomplish.
Observers can view an overhead schematic of the battle site on a mapping module.
A typical briefing by the fire team leader would identify each participant by a computer terminal icon to indicate his role. The leader would designate war fighting positions and outline each marine's role in defensive and offensive modes. These instructions, indicated on the overhead schematic, can be as detailed as individual direction and type of fire at each stage of the operation. As the simulation begins and the marines move out to conduct their operation, the team members call out to each other as they would in combat. Large speakers are positioned on both sides of each team member's computer to provide as realistic a simulated cacophony as possible.