Xbox Gets Military Tactical PlanningCRUISING down Pratt Street in Baltimore along an eerily empty Inner Harbor, Ed Fletcher suddenly yanked his Humvee to the right and barreled into the lobby of the 40-story Legg Mason Inc. building - just in the nick of time as an oncoming dune buggy fired a barrage of bullets at him. Fortunately for everyone, the ensuing gun battle and anarchy werent real. It was just Trex, a video game Fletcher helped design for his employer, BreakAway Games in Hunt Valley. But Trex isnt aspiring to be the next big hit among gamers eager to shoot up a virtual city. Trex is targeting the military - among the latest in game technology being employed for more businesslike pursuits.