"Hang on!" his tiny android likeness yelled. Ed of the dust-grain region drew his Barbara down. They flattened together and clutched part of the intricate but roughly made apparatus attached to the vats from which they had emerged, just as the glassy floor under them tilted, and they were almost swept away by gusts of air. Wires had been disconnected, and now the whole assembly--large microscope with the miniature machine shop, middle-sized tank and middle-sized doll figure under it, and the lesser electron microscope with its similar though reduced equipment--was being carried and hoisted. It was set on a high shelf. And what must have been a translucent jar was placed in front of it to hide it casually. Maybe there was no time for anything else, for that rough vibration of the drill was becoming rapidly more pronounced. "They ought to put on oxygen helmets!" Barbara shouted in the quaking tumult. "These vaults will be unsealed! And they aren't built to live in Martian air!" Maybe the three giants even heard her, through the mike and sound cone. But they would know, anyway. From the twilight of the jar's shadow, Ed could still see into the immensity of the room. The colossi were donning their heavy gear. The vibration had become a gigantic rattle with creaking, crackling overtones, audible only to micro-ears. Ed felt almost shaken apart and dazed by it. Any instant now the drill would break through into the room. But he didn't anticipate much real trouble. It wasn't reasonable. He felt fairly sure that it was the police who had followed his larger self here. They had their duty to give protection, not harm. Their power might be warped by the fears and prejudices of the times, but not beyond reason. He knew that there would be a jolt when the drill came through. So he scrambled over to the pallet and pulled from it a long bit of floss, thicker to him than a rope. Quickly he bent one end around his waist and knotted it, and fastened the middle of it around Barbara. The far end he passed to his uncle. "Tie on!" he shouted. "So we don't get separated. And hold tight to anything solid!" The break-through came, and it was not too bad. It felt like a monster ram hitting the world one sharp, stinging blow; then the spinning mountain of the super-hardened drill bit--all of a yard across, it must have been--braked quickly to stationary. There was no tumultuous outrush of air of earthly composition and pressure. The drill hole had evidently been capped.