From behind the wrecked car someone threw an energy-grenade and then another. The results were a little too good. The whole roof of the tunnel fell in, effectively blocking it to the enemy, but also sealing off any possibility of fighting their way back out through it. Birrel looked around. Thile and Kara and the technicians were still sticking to their task. Down below, on the cavern floor, Shannock had driven back an attack, but from up here Birrel could see the men hiding among the looming machines and knew how badly Shannock was outnumbered. He flung himself down the spiral stair, and the others followed. The loudspeakers roared monotonously overhead, ordering them to surrender. Birrel took up a position behind a huge looming metal bulk and then looked up at the shelf. Thile, Kara and the technicians had disappeared. A second later he saw them coming at breakneck speed down the stair, and in almost the same second something exploded with a blinding flash on the shelf and the transmitter vanished. "Surrender," said the amplifiers. "We will grant you a fair trial if you do, but if you do not you will be killed to the last one. Surrender--" Thile and Kara joined Birrel behind his metal bulwark, panting. "Did you get through?" he cried. "We don't know. There wasn't time to receive acknowledgement." "Here they come!" yelled Shannock. * * * * * And they came, slipping among the looming shapes of potential destruction, firing, killing, being killed, being for the second time driven back. And now for a moment the amplifiers fell silent and another voice spoke close at hand. Vannevan's voice. "Count your dead. You can't replace them, but we can. How long can you hold out?" "As long as there's one of us left!" Shannock shouted back. "That won't be long, will it? Don't be a fool, man. Surrender." Birrel answered him. "You'll be the one to surrender, when the ships come from Ruun." Vannevan laughed. "The Earthman. You still think the Ruunites will fight, eh? They won't." They attacked again, and were again fought off--or rather, Birrel thought, they withdrew, content to hack away at their opponents' numbers without exposing themselves any more than they had to. The amplifiers spoke again. But suddenly the voice had a different tone, and it did not talk about surrender. "A message has just been received from Ruun. Ruunite ships will position over this target in one hour and destroy it. All persons are warned to get clear of the area at once. I repeat that message. Ruunite ships will position--" Pandemonium broke out in the rebel ranks. "You hear that, Vannevan?" Birrel shouted. "You're through." Vannevan did not answer. The amplifiers fell silent. Birrel looked at Thile, and then at Shannock, who said, "They're not going away." "Vannevan," said the amplifiers, "this is Wolt. I am leaving as of now and I advise you to do so. There's no virtue like knowing when it's time to run."