There was a sudden growling uproar where men were crowding to get out of the Shed. Thick, billowing smoke appeared. There was a crashing explosion. The men eddied and milled crazily. The motor of the stalled truck caught. It moved toward the door, which opened, swinging up and high. Two trucks came roaring in. They raced for the Platform. And as they raced inside, their camouflaged loads clattered off and men showed instead. The guards by the doorway began to shoot. "That's what we've got to stop!" snapped Joe. He began to run, his pistol out. There was suddenly a small army--gathered by his orders--which materialized in the dim space under the Platform. It raced to guard against this evidently well-planned invasion. The harsh, tearing rattle of a machine gun sounded from somewhere high up. Joe knew what it was. Mike's whole scheme had been intended to force all sabotage efforts to take place at a single instant. Part of the preparation was authority for Haney to drag in two machine guns from an outer watching-post and mount them to cover the interior of the Shed when the general attack began. Those machine guns were shooting at the trucks. Splinters sprang up from the wood-block floor. Then, abruptly, one of the trucks vanished in a monstrous, actinic flash of blue-white flame and a roar so horrible that it was not sound but pure concussion. The other truck keeled over and crashed from the blast, but did not explode. Men jumped from it. There must have been screamed orders, but Joe could hear nothing at all. He only saw men waving their arms, and others seized things from the toppled load and rushed toward him, and he began to shoot as he ran to meet them. Now, belatedly, the sirens of the Shed screamed their alarm, and choppy yappings set up as the siren wails rose in pitch. Over by the exit pistols cracked. Something fell with a ghastly crash not ten feet from where Joe ran. It was a man's body, toppled from somewhere high up on the structure that was the most important man-made thing in all the world. A barbaric war whoop sounded among the echoes of other tumult.