Intelligence may not be outdated, but rather may have omissions.
Buildings from the Soviet era should logically have backup blueprints or similar archives preserved. However, such information is usually top secret. Decades after the Soviet Union's collapse, certain obvious details don't require consulting archives; for instance, when mentioning architecture, many people know such buildings often have underground bunkers. But beyond that, specifics are impossible to know.
It's known this building can withstand nuclear strikes and that the underground has four levels. These details are nearly public knowledge. However, the specific structure of these four underground levels? Without detailed blueprints, no one can say for sure.
