Sometimes you just did what had to be done.

They’d found him in the water foundry trying to poison the fresh water that poured from the distillation and filtration equipment to support those few thousands left in the city. Not only trying to poison, but poison with the red death, the taint of all natural water sources; the taint that slowly drove you mad.

Had he succeeded, far more would have had to die before a new balance was found.

He knew it, the audience knew it, and the council-appointed judge knew it too. It was only through luck[1] that someone had found him before he could do any serious damage, before anything other than a few tanks had been rendered undrinkable and a few sand filters smashed. They could be replaced and their simple workings were fully understood. Other machinery, far more complex and essential for removing the poisonous red sludge from the river water, had only escaped destruction because the raving lunatic did not know what he was doing.

The sentencing was brief and to the point. The man, still coughing and spluttering his curses to the sky, was to be thrown outside the gate shortly before sundown, left there to die at the hands of that which he claimed to serve.

The man had been drinking the unpurified water.

Tala shook her head in disbelief. All she could do was hope the madness wouldn’t spread. The enforced isolation of the closed-in walls caused enough mental instability without needing to bring the red death into the mix, and the city was the only source of totally pure water she knew. Those who lived beyond the walls used crude methods to filter what they could, and sometimes even she had been forced to do so on extended scouting trips, but no such method was enough to remove the stubborn poison entirely. It was another reason you couldn’t trust anyone from beyond the walls. Every month, every week it seemed more communities had succumbed to the madness.

The man's curses turned to sobs as the jet-black gate came closer and loomed overhead. His furious insults and outraged demands gave way to pleas for a retrial. Tala shut out the desperate offers of things the man could never give, things he did not possess. It was an unexpected change; she had assumed he would still be raving as she threw him out into the waste. Somehow this made it more difficult.

She pushed him through the gap in the gate and stared coolly into the man's violet-tinged eyes as it shut once more. The doors almost took his fingers as he clawed against the hydraulics, an impotent human against the insurmountable pressure of the expanding pistons below.

She heard the laughter of those who scaled the walls to watch as the man began a futile race for his life.

[1] Some argued it was fortune, the hand of some guardian gami who had chosen this city as his fortress. Tala wanted to spit in their faces.