EXDU, pr1s0n, a flooded forgotten prison, black water canal, long rows of rusted iron cells partly submerged in stagnant black water, half-sunken stone staircases, broken ceiling grate, bent iron bars, algae-draped arches and low vaulted ceiling, dripping chains, wet weathered stone, cold teal underwater glow, sparse torchlight and reflections, low fog, epic vertical depth, broad raised dry stone walkway and landing through the center, small carved spiral on a side stone element, cinematic