A few minutes more and Demarzule would be cut off from the air supply. How long it would take to drown him, Underwood did not know. It would depend largely on his present rate of metabolism, which was a great uncertainty. But could the mob be held off that long? They had to be! He bent down and grabbed up the gun that his pursuing guard had dropped. In the background of his mind he wondered what this sudden attack meant. How strongly organized was it, and who was behind it? Apparently Terry had given the signal for attack, and many of the scientists on the project had been prepared for it, yet Underwood had been given not the slightest hint that such attack would take place. He wondered why he had been left out. The screaming of the hysterical Disciples was deafening as those in front tried to force their way back from the line of battle, and those in the rear tried to press forward to glimpse Demarzule. Underwood leaped down to the floor in the sea of confusion and found himself unable to determine which way the conflict was moving. None of the scientists were near him, only the maddened, unreasoning Disciples. He decided to stay near the water valve to make certain that it was not shut off by any of the guards. Then two figures surged up to him and one grasped his arm. "Del! Come on, let's get out of here!" He turned. Terry's blood-streaked face was almost unrecognizable. His other hand clutched Illia's arm. "You two go on," Underwood shouted. "Get out if you can. I've got to stay--to make sure he drowns." * * * * * "The water's cut off! Can't you see?" Underwood turned in horror. The water level was falling instead of rising. Someone had cut it off at one of the other valves farther along the line and had opened the drain. Air was being pumped through, for Demarzule was standing rigidly now, looking down upon the surging mass as if contemplating their fate. The bitter animal struggle for survival was gone now from his face, and only a mocking scorn was there as the mob battled before him. "We've failed!" Underwood exclaimed. "It must have been Craven who shut the water off. We haven't a chance now." "Not if we stay here. Come on. We can lose ourselves in this crowd and work our way outside. There's a ship waiting to take us across to Phyfe. The _Lavoisier_ is manned and ready to go." "The _Lavoisier!_ Where--?" "Who knows? Go!" Hopelessly, Underwood allowed himself to be pushed and jammed into the thick of the mob by the frantic Terry. Signs of armed conflict were dying. Underwood supposed that the scientists had been subdued, for now the hall was completely filled with the Disciples. It was impossible, he thought, that they could ever make their way out without being apprehended. But even as doubts came, he knew that he had to get out. He had to live to make another stand against the Sirenian.