"All right. After you've snapped it in and it releases again, throw it back to me. It may be the last one around, and we're not taking it into the laboratory this time. When the door starts moving down, step back to the right of it. We'll see what the lab is like before we go in." Trelawney indicated a thimble-sized instrument on his suit. "This'll tell whether the place is hot at the moment, and approximately how hot." He waved the IPA gun in Dowland's direction. "All right, go ahead." Dowland fitted the key into the central depression in the door, pressed down, felt the key snap into position with a sharp twisting motion of its own, released his pressure on it. An instant later, the key popped back out into his hand. He tossed it back to Trelawney, who caught it left-handed and threw it over his head in Jill's direction. The disk thudded heavily into the grass ten feet from her. The girl walked over, picked it up, and slid it into one of her suit pockets. The slab of metasteel which made up the laboratory door began moving vertically downward. The motion stopped when the door's top rim was still several inches above the level of the sill. A low droning came from the little instrument on Trelawney's suit. It rose and fell irregularly like the buzz of a circling wasp. Mingled with it was something that might have been the hiss of escaping steam. That was Dowland's detector confirming. The lab reeked with radiation. He glanced over at Trelawney. "Hot enough," the Freeholder said. "We'll go inside. But stay near the door for a moment. There's something else I want to find out about...." * * * * * Inside, the laboratory was unpartitioned and largely empty, a great shell of a building. Only the section to the left of the entrance appeared to have been used. That section was lighted. The light arose evenly from the surfaces of the raised machine platform halfway over to the opposite wall. The platform was square, perhaps twenty feet along its sides. Dowland recognized the apparatus on it from Trelawney's diagrams. The central piece was an egg-shaped casing which appeared to be metasteel. Near its blunt end, partly concealed, stood the long, narrow instrument console. Behind the other end of the casing, an extension ramp jutted out above the platform. At the end of the ramp was a six-foot disk that might have been quartz, rimless, brightly iridescent. It was tilted to the left, facing the bank of instruments. "A rather expensive bit of equipment over there, Dowland," Trelawney said. "My brother developed the concept, very nearly in complete detail, almost twenty-five years ago. But a great deal of time and thought and work came then before the concept turned into the operating reality on that platform."