Drill Sergeant O'Reilly was an Orbital Drop Shock Trooper and instructor at ODST boot camp in 2525. On the second day of training O'Reilly would walk up and down the line, shooting the recruits in the leg with a pistol loaded with Tactical Training Rounds and telling them to run. Those who failed to respond would be shot again. Another major exercise was to place the recruits at the base of a mountain and tell them that if they could neutralize the instructors and make it to the top, they would eat and sleep in their barracks that night. Failure would mean a cold and hungry night on the mountain.