Crossing to the body, he dropped on to his knees and cast about him, expecting to locate the oblong mass of Theo’s power pack either in Lutze’s clothing or on the floor nearby. He was unable to find it. He raised his head and extended the scope of his search, only to discover that in the fitful and uncertain light every piece of litter and builder’s rubble promised to be a power pack and almost immediately revealed itself to be something else. A bomb exploded on one of the floors he had passed seconds earlier, producing the now familiar upsurges of flame and horizontal billowings of dust and smoke. Accompanying the blizzard of paper and plastic scraps there came a heaving of the floor, an uneasy sense of loosening.

Hasson realized that even in the period of dire extremity he had been indulging one part of his nature, claiming the luxury of fastidiousness. He rolled Lutze’s body on to its side, exposing the black-lipped obscenity of the fatal wound, and unclipped the power pack from the dead man’s harness. The unit itself and the electrical connectors were slimed with dark blood. Hasson stood up, clutching the unit to his chest, and loped wearily towards the stairs.

His upward progress was now complicated by the absence of a banister. The prolonged and punishing exertion was robbing his legs of both strength and control. There was an increasing tendency for his knees to buckle and for his feet to come down some distance from their point of aim — but with no balustrade at his side the slightest stumble could have resulted in a one-way trip to the inferno of the first floor. Into the bargain, he was now in a section of the hotel which, for all he knew, had not been traversed since Morlacher had planted his over-powered booby traps, which meant there was a new risk of being swatted into oblivion by an unseen hand. The remnants of his powers of thought told him it was a hazard that would have to be accepted — to get out of the hotel he would have to go all the way to the roof and find the exit used by Barry Lutze and the other aerial trespassers. It was a dismal and dangerous prospect, but the only one open to him.

Having managed to project his thoughts a short distance into the future, Hasson — above the agonised pumping of his thighs and the bellows-sound of his breathing — began to speculate about whether the stair he was climbing would terminate in a doorway to the roof. There had been plans for roof gardens and swimming pools, so it was likely that there would be provision for public access by stair as well as by the elevator service. Spurred on by the hope of perhaps suddenly and easily finding himself outside in the clean starry air, Hasson turned his gaze upward, wondering if he would be able to identify the top landing when it came into view.

In the event there was no difficulty. The entire top storey of the hotel was filled with an impenetrable, rolling layer of smoke and fumes which extended almost from floor level up to the invisible ceiling.

Hasson sank down, winded, on the flight of steps which slanted on to the uppermost floor, feeling like a man under siege as he took stock of his surroundings. The underside of the metres- thick blanket of smoke was defined with surprising sharpness. It shifted and heaved and puckered like the surface of a slow-boiling soup which was being seen through an inverting lens, and there was a thin stratum of clear air between it and the floor. Peering horizontally through the translucent sandwich, Hasson was able to discern the beginnings of yet another flight of steps at the opposite side of the landing. The treads were narrower than those upon which he sat, and the conviction grew in him that they led directly to a door which opened on to the hotel roof.

He forced himself to remain at rest for the space of a few more breaths, gathering oxygen into his system, then he stood up, locked his chest muscles, and ran for the ascending stairway. His feet found the steps seemingly without his guidance, and he hurled himself blindly upwards, going as fast as he could, aware that even one inhalation of the reeking blackness surrounding him could result in calamity. Almost at once a new thought occurred — how could he be sure that the stairs he was now on followed the same layout as those below? How did he know he was not about to plunge over an unguarded edge? Fending the thought off he kept running, trailing a hand along a roughcast wall, until he reached a small landing and a metal door. The door was bolted, padlocked, immovable.

Almost grateful that the door, because of its patent solidity, had not tempted him to waste time in trying to force it, Hasson turned and ran back the way he had come. He reached his starting point just as his lungs were giving out and hunkered down on the steps. Tatters of acrid smoke clinging about him flayed his nostrils and throat, triggering a bout of coughing. He clung to the steps until the convulsions ended, a part of his mind disdaining involvement, using the moments of astral detachment to analyse the situation.

From the moment he had entered the Chinook Hotel his life had depended on interplays of forces. Some of the factors he had contended with had been human, others had been purely physical — and not all of them had worked entirely to his disadvantage. The design and topography of the building, for example, had conspired to give him some respite, some time to manoeuvre. A fire was like a primeval jet engine, needing air intakes and an efficient exhaust before it could attain its full deadly splendour. The fact that the roof of the hotel remained unvented and intact — as evidenced by the trapped pall of smoke — had denied the fire the upward exhaust it craved, slowing its progress, cramping its natural style. Had the layer of smoke and fumes not been able to form, he, Rob Hasson, would no longer be alive, having been engulfed and incinerated at a much earlier stage. It was unfortunate-though no indication of malice on the part of the physical world — that the same toxic cloud was now making it impossible for him to search for the only escape route to the outside universe…

Far below Hasson a cataclysm overtook part of the edifice of sloping stair beams upon which he was poised. There was a gargantuan shuddering and thundering which suggested that whole flights of stairs were breaking free of their supports and dropping like carelessly released playing cards. Currents of hot gas geysered up through the central well beside him, churning the overhanging canopy of smoke.

Hasson uttered an involuntary moan as the staircase on which he was perched gave a tentative lurch. He crawled forward on to the floor proper, pressing himself downwards to stay within the wafer of lucid air, holding his breath each time a disturbance enveloped him in the smothering lower reaches of the cloud. Even at floor level the air was now so polluted as to abrade the tissue of his lungs, and he began a slow steady coughing. A lurid redness began to pulse in his vision.

Hasson blinked his eyes, squinting ahead through his two-dimensional continuum, making the belated discovery that the shifting red light was not a subjective phenomenon, but something that had its origins in the external world. Driven by impulses beyond his understanding, he squirmed forward, towards the source of the intermittent radiance. Eventually, an incalculable time later, he found himself lying on the shore of a circular lake.

He shook his head, trying to restore a sense of scale, the ability to relate to his environment.

What he was seeing was not a lake, not a pond, not a pool. It was… an elevator shaft.

Hasson looked down into the shaft — narrowing his eyes into slits to combat a hot upward draught — into its dwindling, receding telescopic sections, the alternating concentric rings of darkness and orange fire which had at their distant hub a small, black, unwinking eye.