Imperium of Man, Adeptus Mechanicus, Squats
In a demented age of ignorance and cruelty, the gates of death stand ready to shut close on man.
Wind, rain, snow, sandstorms and beasts have ever afflicted man, and so to escape the forces of nature he built for himself a sanctuary and called it home. The very earliest means of covering the entrance to tents and huts was to hang the hide of an animal over the opening. Later on during the Age of Terra, man invented doors from reed and wood, and as his ingenuity grew, so too did the various forms of gates and doors increase by ever more clever means, including the fabled energy seals, living gates of Vigemusque and voidposterns of the Dark Age of Technology. And no matter the epoch and techno-sorcery at hand, man would not think twice about opening a door to enter or exit a room or a building, and would not count the times he crossed the threshold on his way to and fro other matters. It was just a door. And man ascended in worldly matters.
As punishment for his hubris, Man of Gold was toppled from his paradisal pedestal after Man of Stone and Man of Iron had disappeared amid havoc, and almost all the creations of humanity burned during the subsequent Old Night. Thus most works were lost forever, and but scraps of ancient glory remained to be rediscovered by primitive survivors in the charred ruins. Among the salvaged technical systems (hailing from wildly different levels of tech-advancement) were crude but effective variants of humble doors, easily replicated from among the very simplest of Standard Template Construct (STC) hard-copy blueprints. These included sturdy blast doors and vault portals, as well as simple domestic constructs, bulkhead entrances and more flamboyant silent weighed gates favoured by many Ecclesiarchal cathedral builders.
Many variants of high-speed doors were originally designed for industries in order to speed up production logistics and aid in temperature and pressure control, not to mention their widespread duty for pharmaceutical clean rooms during lost ages of human science and progress. In the rotting Age of Imperium, however, such high-speed doors have become commonplace almost everywhere across the star-spanning domains of the Emperor on Earth, known as autodoors among those who bother with the correct technical term.
Something as simple as an automatic door stand as a mute testament to the debt mankind of the regressed Imperium owes to those who came before. Most STC autodoor blueprints included split-second safety systems in order to avoid harm and injury. Yet all across the galactic dominion of the God-Emperor, the machine spirits of doors kill, maim and crush tens of thousands of people every day across hundreds of thousands of worlds and uncounted voidholms. STC progeny though most of these autodoors may be, the safety measures originally designed for such gateway devices in ancient times are nowadays often broken down or lacking altogether.
There are a multitude of reasons behind this rotting state of affairs. For one, incremental loss of technological knowledge over many thousands of years have been accompanied by a decay of production processes, leading to a great many finer and non-essential electronic and automotive systems not functioning as they should, or at all. Oftentimes, reductionist logistical calculations will result in Manufactoria masters and Administratum bureaucrats ordering the removal of fully functioning but unnecessary safety features in order to save on material consumption or increase the rate of production by simplifying and making designs more rudimentary. At other times, faulty maintenance is to blame for the common phenomenon in the Imperium of Man that is death by doors.
Imperial modes of thinking run at best along lines of callous indifference to human suffering and demise. Yet the hunger for cruelty and hardships inflicted upon others may often extend far enough so as to become outright murderous as a result of deliberate planning.
After all, is it not virtuous to construct an environment that will punish the weak and unworthy, and leave those strong and worthy in the eyes of His Divine Majesty to prosper and populate the star-spanning realms of mankind? Is it not pious to build hazards and dangers into buildings and starships, in order to encourage swift wits, sharp eyes and alert senses akin to those of our eagle-eyed Imperator Himself? Is it not healthy eugenics to cull the slow and the weak among us in order to breed a fitter human species for the greater glory of the Emperor of Holy Terra? Is it not for our own good that so many autodoors shut close with sudden rapidity, with such lethal force and disregard for human health and safety? Is it not praiseworthy to develop wits and fine habits of avoiding such everyday dangers as sliding doors and portcullises? Is it not righteous to let the idiots, fumblefoots and deviants get caught in gateway traps due to their own faults, instead of indecently sparing them the clamping test?
Spare the rod and spoil the child. It is better that a thousand accidents choke humans to death between twain doors or crush them under gates, than a single careless sloth of a wastrel soul walks alive among us, naïvely heedless of the caprice and rhythm of dangerous doors while he puts his trust in installed sensors and failsafes without thinking and caring for himself among the corridors and mazes of hive cities, starships and voidholms. The fact that the hearts of uncounted millions upon millions of Imperial subjects are gnawed by entamaphobia, a fear of doors, is only proof of the sound survival instincts cultivated by living and working in Imperial installations.
Furthermore, it happens to be that the common existence of lethal door devices every day aid righteous servants of the Imperator by providing convenient implements of improvised torture and summary execution, all spectacularly visible as warnings to the masses of bystanders and passers-by. If a lowly debt-slave, scrivener or indentured labourer happens to display thoughts of self, heretical insubordination or sinful aspirations above his station, then a just master is at liberty to display his or her power by deed on the spot, through swiftly arresting and excruciating the malcontent, degenerate or apostate by having their underlings heave the damned felon into the jaws of a nearby blast door or portcullis. Naturally, the same handy availability of rapid sliding doors without safety mechanisms have also stood innumerable gangers, bullies and criminals in good stead, to the detriment of hordes of victims across the centuries. No matter, for they too foster a hardier spirit in the subjects of the exalted Terran Emperor.
A logical consequence of this devious Imperial mindset can be seen in certain installations' entrances to areas off-limit yet not of high importance. At such locations, some doors may be rigged to seemingly allow entry, only to instantly slam shut as a deadly biting trap upon those who fail to enter the correct passcode.
Another product of simple Imperial engineering are slice-gates and cutdoors, which act akin to guillotines by sporting sharpened ends in order to make short work of any foolish deadbeat or sneaking street urchin that disrespect the machine spirit. The resultant local cleaning duty is offset by the higher value of cleansing the populace of unwanted elements by allowing them to sort themselves out by impious incompetence. After all, the bio-recycling corpse grinders ever hunger for the dismembered remains of despicable unworthies, and so lesser men end up feeding their betters in the form of corpse starch, true to the eternal food chain of beasts and men alike.
Indeed, a common Imperial proverb instruct us that a good subject is like a good door: He shall be alert to commands, fast in executing orders, ruthlessly powerful and unyielding in his single-minded work purpose in life. And he shall halt for no one, once assigned his task by his superiors.
As a door is but a component of a facility, so too is a humble human nought but a replacable part in a vast, faceless machine operating on a broken equation of increased input. For all those modes of invention and sharpening of efficiency (once pursued by sinful forefathers out of foolish dreams of becoming like living gods) have long since been forgotten in fevered ages of darkness and blood, as mankind spiral ever downwards into depravity.
And so trillions of men, women and children across the Imperium of Man will include a line in their daily prayers, for the God-Emperor to preserve them from the crush of gates, the clipping doors, the fast exit, the hydraulic death. For habit is a strong force in the heart of man, and he is capable of living under any conditions as though they could be no different. As his distant ancestors once endured predators, travails and savagery, so too will their descendant of the far future endure the deadly environs which man has crafted for himself across the stars, among glittering spires and baleful hive-sinks.
For man's lot is suffering and death, and all that is given man is a chance to serve the lord of his species during his miserably short life. Serve, toil and die.
And everywhere, doors close shut on fragile hope as decay slowly worsens, ever more.
It is the fortyfirst millennium, and there is no way out of the horror and despair.