Bob was after him in a moment. The door, he already knew, had no fastening on the outside. He pulled it open, and, followed by Ah-Sam, dashed into the corridor after the fugitive. He heard the pad of rapid footsteps ascending the stairway. Springing up as fast as the narrow winding steps allowed, he gained the roof just in time to see, in the thin light of dawn, the gigantic Manchu disappearing through the opening opposite. Bob leapt across the roof to follow. Down the stairs he plunged, staggering, recovering himself, gaining on the heavier man in front of him. So eagerly did he pursue that he forgot the existence of the door at the foot of this staircase, until, coming suddenly full tilt against it, he was brought up with a painful shock that rendered him almost breathless. He remembered that the door fastened on the other side; had there been time for Chang-Wo to slip the bolt against him? He pressed it; it did not yield; he went back a few steps and flung himself against it. There was a creak, a slight yielding; pray heaven the bolt is old! Ah-Sam is by his side. Together they hurl themselves against the door with all the force the confined space admits. The bolt is torn from the woodwork, the door flies open, and the two dash through. But with this interruption Bob bethought him of the man he had felled in the kitchen. He might, he would, recover consciousness, and alarm the garrison. "Back!" he cried to Ah-Sam, halting for an instant. "Back, and secure that man. Do not kill him."