Being an expert on a particular machine ensured that Tarn could work it to its maximum capacity, keeping everything running fluidly. That made the guards very happy.
It also meant he knew exactly how to break it.
More importantly, he could do it in such a way that it would take a long time for anybody to realise he'd done it deliberately.
After he'd given up the fight they'd beaten him; dragged him to the centre of the chalk circle and all had a go, with feet, hands, sticks and anything else they could find. Then one of the guards had stopped it, and told them to ease off before they gave everyone a problem. That guard had pulled Tarn back up on his feet and marched him out of the fighting room. There was a time when Tarn would have thought that meant he had a friend but now he knew it was because if he was injured he'd be unable to operate the machines properly. They couldn't afford the downtime.
Through the bruises and the cuts and pain, Tarn could feel his world becoming a little clearer, like on the days when the machine rooms would start off full of steam, making it hard to see, and then slowly become visible as the vapours disappeared and drifted away.
His next shift was difficult, as his body ached from head to toe and pressing the right buttons at the right time required more concentration than usual. He did his best, so that the guards didn't punish him further, and while he worked he continued to think about the pipes, and the ceiling of the machine rooms, and what could be hiding above.
Strongest of all was the desire to leave. Strange that he'd never thought about it before, as if the idea had always been just out of view and he'd only now turned his gaze towards it. As he carried on working, in his mind he started to run through an alternate sequence of working through the machine, changing the pattern of cranks and levers and wheels to a very different purpose. A plan started to form.
Three shifts later he had mostly recovered from the beating in the fight room. There seemed little point in delaying any longer. Each day spent with the machines was another day to be involved in an accident and lose an arm or a leg.
Changing how he was manipulating the machine's controls wasn't difficult, or even risky. None of the guards understood how anything worked down here, while all the other boys would be focused on their own jobs. Besides, nobody here deliberately caused problems - mistakes happened regularly, but nobody would dare risk sabotage. He pressed his buttons and pulled his levers.
The first consequence was a vibration in the metal gratings on the floor, fast and light at first then building to an irregular, hard knocking that was felt throughout the room. The machines starting venting far faster than normal, then the huge wheels slowed and ground to a halt, pistons falling silent. He hadn't caused any real damage - he knew that would only cause difficulties for the other boys after he was gone - but the entire room was shut down and would remain so for some time.
It occurred to Tarn that the workers held all the real power down here. They tended the machines and kept them running, while the guards had no knowledge or understanding of their complexities. Their only skill was in punishment and discipline. If all the workers refused to work at the same time, what would the guards truly be able to do?
Putting the thought to the back of his mind, Tarn focused on the immediate situation. The other boys were looking around in silent confusion, some of them examining their machines in attempts to identify the problem, while guards were shouting at each other with increasing panic in their voices. One guard ran down a ramp in Tarn's direction. Smiling helpfully, Tarn said "Fix?" as he passed.
The guard stopped and turned. "You know how to fix this?" he asked, sceptical.
Tarn nodded, then pointed at the pipe - the same one he'd been in before. The guard followed the direction of his finger and sighed. "Follow me," he said, and led Tarn up to the higher gantry. Pulling the key from his pocket, the guard did the customary check then swung open the hatch. Some steam hissed out but the pipe was quiet and inactive. Tarn hid his relief - he hadn't been sure his plan would work.
Climbing inside, he started to descend the ladder, keeping one eye on the guard, who started to pace back and forth on the gantry. He spotted one of the other guards on the floor below and shouted to him, moving away from the hatch to lean over the railing. Tarn took the opportunity and climbed up as fast as his arms and legs would take him, hauling himself up past the open hatch to the ladder above. He kept going, bringing his legs up as fast as possible so that they wouldn't be visible from outside the pipe.
Then he kept going.
Rung after rung, he climbed up into the darkness of the pipe. He was aware of the glow of the hatch below, shrinking with each climb of a rung, until he suddenly reached an opening where the ladder ended and the pipe angled around to be horizontal. Pulling himself up and over, he sat for a moment on the curved floor of the pipe, regaining his breath. The walls of pipe were still hot and covered with water droplets. Up here it seemed cleaner than the one he'd gone in at the base of the machine rooms.
Waiting here wasn't an option. He had no idea how long it would take them to discover what he'd done to his machine and find someone who could undo it, but once that happened and the machines started moving again the pipe would be filled once more with boiling hot steam, gushing through to its unknown destination. He could only assume that he didn't have long.
He crawled along in the darkness, feeling ahead with his fingers, wary of falling down an unseen shaft. Soon the pipe forked off in two directions, so he picked one at random and carried on. There was no way of knowing the correct route and therefore there was no reason to pause and consider. The pipe came to an end and he felt a sense of rising panic, before finding a route above his head. There was no ladder here, so he braced himself against the walls, with his back against one side and feet on the other, then started shimmying his way up. Blackness enveloped him on all sides, leaving him with no guess at how tall the pipe was or for how long he would have to climb. All he knew was that he was higher than he had ever been his whole life. Perhaps everything was dark when you were this high up, with the only light in the whole world found down in the machine rooms.
On he went, following the course of the pipes, trying to swallow his fear. As he'd lain in his sleeping hole before the shift he'd tried to think of way to take Fiffdee with him but it would never have worked. He'd come back for his friend, if he could. Although Fiffdee might be better off staying where he was, where there was food, and sleeping holes, and occasional showers.
Living in the constant light and noise of the machine rooms, Tarn had never developed a strong understanding of the passing of time. Now that he found himself in the darkness of this system of pipes he became acutely aware that he had no comprehension of how long he'd been there, or how far he'd travelled. There were no references with which to anchor himself in time, or space. Instead, he scrabbled in the darkness, always moving forwards and up through the maze, utterly lost and unable to retrace his steps.
Echoes reverberated up and down the pipes, the repeating sounds of his own movement creating the impression of being surrounded in the dark by other escapees. There was nobody in here with him, he was sure. No life existed here, though he expected at every turn to encounter another melted body. Odd clangs sounded intermittently, each one intensifying the anxiety that the machines were turning again.
He put such thoughts away and carried on. He was afraid but did not regret his actions. If the steam returned, washing through the pipes, boiling hot and fast and angry, and destroyed him he would still be in a better place than he had been: of that he was sure. Something had been building inside him, giving him courage and conviction, convincing him that it was better to die while searching for answers than to live forever at the face of the machines, pulling endless levers and doing what he was told. If disappearing into these pipes was the first and last decision he ever made for himself, it would be enough.
The clattering noises, far distant, became louder, prompting him to increase his pace. He shuffled forwards as fast as he could, barely checking in front of him in case the pipe took a sudden downward turn. Haste was everything.
Then the pipe shrank, becoming progressively narrower. He kept pushing forward, ducking his head as the ceiling dropped, then shifting his elbows in as the walls drew closer. He was forced down onto his belly, wriggling forwards awkwardly, dragging himself through the pipe with his fingernails. Turning around was no longer an option, and if the pipe narrowed anymore he would become wedged and trapped.
Still he did not panic. Instead, he gritted his teeth and a low, guttural growl started to rise in his throat, intensifying with each difficult drag onwards. The noise of his own movement prevented him from hearing anything else and he didn't dare stop to listen behind. The steam was coming or it wasn't; there was nothing he could do to change that. Movement was all that mattered.
The pipe began to vibrate, the rattling intensifying. He kept going. A roar began to build, the shout of an approaching mechanical monster, still a long way back through the maze. It was unlikely that they'd realise he'd deliberately escaped; they would instead assume he'd become lost. If somebody else was able to fix the machines, they wouldn't bother to send anyone to search.
Something blocked his way. The pipe came to an abrupt end. His fingers scrabbled at the obstacle in the darkness, trying to identify what it was and whether it could be moved. As his nails scraped at it, he could feel years of sludge being scraped away, layer by layer. Then, there was light. A pinprick at first, then a sliver. As he pulled his fingers desperately across the caked dirt, dragging it out the way, more light trickled in through a fine mesh that was fixed in place. The holes in the mesh were too small for him to see through but large enough for light to stream in, enabling him to see his hands in front of him for the first time since he'd entered the pipes.
He dug furiously, pushing the dirt down the sides of the pipe either side of him, and underneath his chest, using the light to examine the mesh. Around its outer edge was a thicker piece of metal and as he felt around it he found three clasps which were holding it in place. He concentrated on one and pulled at it, with no success. Tucking his nails underneath, he yanked upwards forcibly. His nails bent and started to tear away from his fingers, but then the clasp flicked open with a snap. Moving on to the next he did the same, fixing his bleeding fingers below the clasp and pulling at it, focusing as much strength as he could into the tips of his fingers. At first it did nothing, then it started to flex and then, finally, clicked open like the first.
Pushing at the mesh, Tarn repeatedly punched it, causing it to buckle, then swing outwards on its one remaining clasp. He saw beyond the pipe, which opened out into a much larger tunnel - still dimly lit, but bright in comparison to the network of black cylinders he'd been crawling through. Taking hold of the edges of the pipe, he pulled himself forwards, all the dirt and sludge making movement harder than it had been before.
The pipe rattled angrily and the roar increased in pitch to a shrill shriek. He poured his determination into his arms and managed to move a little further, then a wave of intensely hot pressure hit his legs, and he found himself propelled forwards and out of the pipe, then thrown halfway across the tunnel to its far side, where he fell into shallow water and rolled onto his side. Steam shot out of the pipe and vented into the air, where it dissipated and fell as a mist.
Taking in his surroundings, Tarn found himself in a long, brick tunnel, stretching away in both directions. At intervals along the tunnel bright light poured in from above, shining through small, square openings. He squinted, the light burning his eyes, brighter than anything he'd ever seen.
Tarn's feet and legs were sore from the heat of the steam. His elbows were raw from crawling. His fingers were bleeding from the fingernails where he'd forced open the mesh covering. Filth covered him from head to toe. There was no part of his body which did not hurt. Yet as he lay on the floor of the brick waterway, he smiled, and laughed, and enjoyed his first taste of freedom.