Ennis plunged through the whirl of unseen bodies in the direction of the detective's shouting voice. He smashed through, half dragging and half carrying the girl, until Campbell's voice was close ahead in the dark. He fumbled at the rock wall, found the door opening, and then Campbell's hands grasped him to pull him inside. Hands grabbed him from behind, striving to tear Ruth from him, to jerk him back. Voices shrieked for help. Campbell's pistol blazed in the dark and the hands released their grip. Ennis stumbled with the girl through the door into a dark tunnel. He heard Campbell slam a door shut, and heard a bar fall with a clang. "Quick, for God's sake!" panted Campbell in the dark. "They'll follow us--we've got to get up through the tunnels to the water-cavern!" They raced along the pitch-dark tunnel, Campbell now carrying the girl, Ennis reeling drunkenly along. They heard a mounting roar behind them, and as they burst into the main tunnel, no longer lighted but dark like the others, they looked back and saw a flickering of light coming up the passage. "They're after us and they've got lights!" Campbell cried. "Hurry!" It was nightmare, this mad flight on stumbling feet up through the dark tunnels where they could hear the sea booming close overhead, and could hear the wild pursuit behind. Their feet slipped on the damp floor and they crashed into the walls of the tunnel at the turns. The pursuit was closer behind--as they started climbing the last passages to the water-cavern, the torchlight behind showed them to their pursuers and wild yells came to their ears. They had before them only the last ascent to the water-cavern when Ennis stumbled and went down. He swayed up a little, yelled to Campbell. "Go on--get Ruth out! I'll try to hold them back a moment!" "No!" rasped Campbell. "There's another way--one that may mean the end for us too, but our only chance!" The inspector thrust his hand into his pocket, snatched out his big, old-fashioned gold watch. He tore it from its chain, turned the stem of it twice around. Then he hurled it back down the tunnel with all his force. "Quick--out of the tunnels now or we'll die right here!" he yelled. They lunged forward, Campbell dragging both the girl and the exhausted Ennis, and emerged a moment later into the great water-cavern. It was now lit only by the searchlight of their waiting cutter. As they emerged into the cavern, they were thrown flat on the rock ledge by a violent movement of it under them. An awful detonation and thunderous crashing of falling rock smote their ears. Following that first tremendous crash, giant rumbling of collapsing rock shook the water-cavern. "To the cutter!" Campbell cried. "That watch of mine was filled with the most concentrated high-explosive known, and it's blown up the tunnels. Now it's touched off more collapses and all these caverns and passages will fall in on us at any moment!"