Desperately Pell strived to keep his legs under him, but they wobbled in spite of his control and he fell. His arms and legs were mere dead weight; he could no longer force them to do his bidding, not even to the extent of releasing the stud on the blaster. A wave of heat struck him mightily on the face, as if he had been thrust bodily into an atomic furnace. Then from somewhere a draught of cool, pure air played about him, washing the fumes of the nerve gas from his system. * * * * * Astounded, Pell gasped in deep lungfuls of the precious air and painfully stumbled to his feet. Slowly the incredible truth dawned upon him. Accidentally he had blasted open the sliding steel door of the elevator shaft and the cool breath of its untainted air had revived him. Hastily he looked around him, trying to spot more of the enemy creeping through the dense fog toward him. There were none; apparently they had decided to let the gas do its work. They were in for a surprise, Pell reflected. An idea had occurred to him. He might just possibly escape the trap by climbing up the inside of the elevator shaft. He strained his eyes into the dimness of the shaft and found what he was looking for; a frail-looking steel ladder which extended in both directions up and down the shaft. Looking up, he tried to pierce its puddled blackness but could see nothing. If a dropper should hurtle down out of that blackness, he would be smashed to a bloody pulp. Grimly he thrust the thought out of his mind, slung the blaster over his shoulder, and leaped for the ladder on the far wall of the shaft. It trembled dangerously as his writhing body struck it and swiftly he began his long climb into the darkness above. For what seemed an eon of agonizing effort, Pell hauled his weary body up the length of the steel ladder. It stretched up and away into an infinity of blackness that housed a sudden and terrible death. As he climbed, Pell strained his senses in the all-enveloping darkness but could perceive nothing. Suddenly his hand, groping for another rung, met nothing but emptiness and for one terrifying moment Pell tottered off balance on the ladder. Cautiously he felt about above himself and his hand collided with the underside of a dropper which was suspended just over his head. Had he reached the top? It was impossible to tell in the blackness. He had no choice but to chance it. Saying a silent prayer, Pell unlimbered the blaster and wrapped himself about the tiny steel ladder as tightly as possible. Then he loosed its devastating radiance at the wall opposite him. The brilliance of its destructive flash blinded him momentarily as he clung tenaciously to the frail ladder which whipped treacherously.