Ms. Shinnick said she had become somewhat inured to worries about an attack. In less than two years, she noted, Washington (D.C.) workers had endured the Sept. 11 attack on the Pentagon, a sniper who stalked the suburbs, anthrax scares, and a protest this week by a disgruntled tobacco farmer who threatened to blow himself up. "If something's going to happen, it's going to happen," she said.