Beyond conducting their periodic evaluation of Womack Army Medical Center, one of the military's busiest hospitals, the inspectors who came here to Fort Bragg last March had a special task. A medical technologist had complained of dangerous lapses in the prevention of infections. The inspectors planned to follow up. But Teresa Gilbert, the technologist, said supervisors excluded her from meetings with the inspectors from the Joint Commission, an independent agency that accredits hospitals. "I was told my opinions were not necessary, nor were they warranted," said Mrs. Gilbert, an infection-control specialist.