Marines treated at Camp Lejeune for post-traumatic stress had to undergo therapy for months in temporary trailers where they could hear bomb blasts, machine-gun fire and war cries through the thin walls, according to servicemen and their former psychiatrist.The eight trailers were used for nearly two years, until a permanent clinic was completed in September in another location on the base, said a Camp Lejeune medical spokesman, Navy Lt. j.g. Mark Jean-Pierre.