They worked for twenty-four hours straight. Elara identified the three primary acoustic and structural resonance points of the building: the sub-basement boiler room, the Chancery echo-chamber, and the main elevator shaft.
She rigged them to release controlled bursts of low-frequency sound at precisely timed intervals. It wasn't loud to human ears—a low, rhythmic throb that felt more like a headache than a sound—but to Mnemosyne's sensors, it would be catastrophic. It would create a harmonic cascade that would make the building's data twin vibrate like a bell.
In parallel, Julian created a data-mirage. He fed a stream of false information into the building's sensors, simulating a massive, imaginary load that matched the physical vibration Elara was creating. He was simulating a 'Consciousness Event' within the building's infrastructure.
The scan began at 3:15 AM.
In the Oculus command center, the screens went wild. The twin of The Obsidian didn't just flicker; it screamed. Mnemosyne, interpreting the massive acoustic and data load as a 'structural-awareness cascade,' immediately prioritized analyzing the anomaly. It diverted 99% of its resources to understand how a brick-and-stone building was exhibiting the hallmarks of a sentient AI.
While Mnemosyne analyzed the imaginary ghost, Julian performed a final, massive data-erasure. He snipped the links to Helena Valerius, wiped the files in his closet, and de-indexed himself and Elara from all city logs. He made them as silent as the stone they lived in.
When the 'event' finally subsided an hour later, Mnemosyne reported: Anomaly cataloged as unique architectural resonance pattern. No human intelligence or sensitive data detected. The Obsidian was no longer a zero-traffic sector. It was now an unique, scientific curiosity.