A withered city

solution
Getting keycard c (requires blowtorch): Walkthrough

Getting unknown material fragment: the tunnel > enter the sewage system > go east > continue > north: a strange cube > loot > south > south > west > exit event

a withered city
sprawling skyscrapers tower overhead, triumphed only by the massive sinkhole that has swallowed every road in sight. smaller buildings have collapsed into it, spilling rubble everywhere, while the bigger ones’ support beams are exposed to the open air. the hole is long and wide, encompassing most of the city from where you stand, but it doesn’t seem to be too deep. as you walk forward, you can see a path is made through some cracked roads laying over the debris toward an underground tunnel.

the tunnel > the tunnel | leave

dark tunnel
you can see a murky liquid gently trickling out of the tunnel as you approach it, the towers rising higher overhead. the tunnel is rectangular, with an indent at the bottom to let the liquid leak out. it’s the entry to a sewage system, its sparse fluorescent lights somehow still glowing despite the destruction.

enter the sewage system > dark tunnels | leave

...

a strange cube (Looting)

 * +1 unknown material fragment

a perfect cube, cut from some unknown material, juts out from the dead end ahead. it glows purple, its hue shifting slightly as your view of it changes angles, and it hums loudly.