When five minutes had passed he stepped onto the stairway, pulling the steel door shut behind him and locking it. He had taken only a couple of steps down the winding stairs when he heard a distinct, flat sound. He went rigid. Motionless, his muscles taut, he waited, listening intently. The narrow aisle along the floor of the tunnel was dimly lighted. High on the stairway he was almost lost in shadows. The sound had been that of a door closing gently under its own power--or slowly eased shut. No more than the click of a latch, magnified along the tunnel. Now there was only silence. He didn't want to be caught here. No explanation would be accepted without an investigation--and there would be signs on the surface revealing that two people had been out together, a man and a woman. Slowly, setting each foot cautiously onto the metal steps, he began to descend. When he was low enough he leaned down and away from the staircase to peer along the tunnel. The service tunnel fed into a larger passage. There was a door at this opening, and another between the passage and the air conditioning-heating room. The door at the end of the tunnel was open. Perhaps Ann had left the farther door slightly ajar, and a slight current of air had caused it to click shut. Still.... Hendley reached the bottom of the stairs. Keeping close to the maze of pipes along one side, he edged forward. A shadow moved across the face of the tunnel. Hendley squeezed close to the pipes. One of them carried hot water, and he had to suppress a gasp as his hand touched the hot metal. After a long moment he moved his head out a few inches--just far enough to catch a glimpse of the opening at the end of the tunnel. A shoulder came into view, bearing the emblem of a security guard on a green sleeve. Hendley eased back against the pipes, setting his teeth against the heat from the one pipe that seared a bar of pain across his back. If the guard took one or two steps into the tunnel--or even leaned through the door to get a better angle of view--Hendley would be visible to him. Hendley breathed very slowly and silently. His legs were beginning to quiver from the strain. Either the guard didn't suspect his presence, or he was unwilling to enter the tunnel alone, making himself a vulnerable target. What had drawn the man there? Had Ann been seen leaving? Surely not--the guard's investigation would be more thorough. Had he heard a suspicious noise then, the noise Hendley had made closing and locking the outside door? Or was this simply a routine inspection? The tunnel darkened suddenly. The steel door clanked shut, sealing the tunnel off from the adjoining passage. In the dim light remaining from the tunnel's own illumination panel, Hendley stepped away from the pipes into the center of the aisle. He let out a deep breath.