There'd been a tunnel collapse three weeks ago. Oksa hadn't worried too much. It was a big, big cave, hastily dug. It had started as an extension of the subway tunnels into bomb shelters when the bombings had started aboveground, and then for half a century the bombings had not stopped, and the caves had been expanded and expanded and expanded, farther downwards as the bombs got bigger and more dangerous. Twenty-eight million people had lived in the city, once, and most of them were dead but still millions of them now lived beneath it. That was not how you were supposed to build caves, and it was unsurprising that sometimes there was a tunnel collapse. She'd looked up the obituaries, donated a little money to their children.
There'd been another one a week later. Bigger and worse, cutting off a sizable artery of the city. That wasn't the kind of thing that could be expected every once in a while. It might've been the Elves, testing new underground weapons that could shake the world violently enough to destroy all the underground cities. That'd destroy the Elves, too, of course, but perhaps they didn't care. If everyone fell into the Elf gods' hands wasn't that an Elf victory? The Elves didn't have any children, she'd heard. Maybe if your own cities were empty of innocents and empty of laughter then it didn't seem like it mattered if the world kept spinning.
Two days after that the ground had lurched under her feet on her way to work and the baby had bitten his tongue and ten tunnels had collapsed. A couple thousand people had met that night in an old subway station, big and stably built by Dwarves before the war, and huddled there and talked about leaving, maybe. In Angband you could live above ground, because the Elves didn't dare venture near. Angband was crowded and probably all the housing was below ground but even so, you could take your children up aboveground, sometimes, and show them the stars.
You heard bad things about Angband too but, then, all you heard were bad things these days.
Five days later while they were trying to convince Angband to send an escort for them there was the worst earthquake yet, the city sundered into four or five pieces, some of them likely without any ventilation. They'd decided to leave without the escort. They'd had to use a set of emergency escape tunnels whose trajectory didn't match their map. They reached the surface and started walking, possibly in the entirely wrong direction. There were seven thousand of them. The children gaped at the sky. She couldn't, it turned out, show them the stars, because at some point in the last fifty years the sky had filled with too much soot for any stars to shine.
They debated briefly whether to start walking right away or to wait until the sun rose and it became clear what direction they should be walking in; they decided to start moving, because if they were spread out by the time they were visible to Elves they'd be a less tempting target for bombs and missiles, and because Akka was 90% sure this was the right direction.