By CHRISTOPHER TORCHIA, Associated Press NAIROBI, Kenya (AP) — Hiding from gunmen in an office building, a group of people heard gunshots getting louder and the clatter of a weapon being run along the metal banister of a staircase, according to a survivor of an Islamic extremist attack in Kenya last week. Then a gunman opened the door of the room where the workers huddled, said he was with al-Shabab