The thing about Milliways is, time is funny. Trollian already plays fast and loose with ideas like continuity, and when Karkat thought about combining the two timey-wimey balls of behemoth shit, he got a terrible pain in all the foreboding glands down his left side. He noodled around with it for a while, finally determining that he needed to close out and reboot his modified program with every new iteration of the observation window.
This was convenient, because ~ath coding is specifically designed to link events to the death of an external destructor, such as a universe. But the problem was, well, the universe starts right back up again. His first few attempts at coding his way around the problem failed in complicated tangles of continuity; more than one computer detonated under the strain of jammed timelines. It wasn't until he thought of finally using Sollux's curse program--the one that killed his lusus, the one that ruined everything--that it all came together for him.
That program was designed to bifurcate, and only execute when the universe both did and did not exist at the same time, as he understood it. It was therefore a reality-torching curse program in most locations in Paradox Space, dumping massive zemblanity overflows into the local reality and steering reality as hard towards nonexistence as it could, rather than wait patiently--but Milliways was special. Once he figured out how to index the universe being called to the one outside the bar window, it was the perfect solution.
He made one error, which he never noticed until he had already turned the server loose to fend for itself in the mountains.
He had forgotten to close the loop. It was a simple error of syntax, putting the DIE command on the wrong side of a bracket, and there was no way it could ever cause any harm even once he knew it was there. The function would merely be called again and again, each time the universe window looped, without ever closing out; instead of periodic spikes of zemblanity, a rising tide of negative synchronicity. But the bar is shielded from the ill-luck of the doomed universes outside, up to a rating of 1.9 yottageddons. Someone would have do something
seriously stupid to the shields to allow a zemblanity leak into the bar itself.
Of course, it's always good coding to go back and close loops, even for cases you never expect to come up, and there was always the chance that it would overtax the server, despite a truly ridiculous amount of RAM. Karkat promised himself he would definitely get around to fixing it. After all, the server would surely need to be overhauled after the first bugs were worked out, anyway.
But the server worked fine, and in any case, due to a mutation in its self-preservation AI and the depredations of the demonbunnies, it vanished into the woods, careening around on its mechanical crab legs, and he never found it again. He shrugged it off and felt, for the most part, pretty good about himself for a change.
Minus that little glitch, it was the only
perfect program he had ever written.