A pretty robust secure room even from many decades ago would combine isolation tricks you would see in various single-purpose laboratory settings and in hollywo

A pretty robust secure room even from many decades ago would combine isolation tricks you would see in various single-purpose laboratory settings and in hollywood movies. A room within a room with non-parallel walls for acoustic isolation over a wide frequency range. The inner room is hanging from a spring suspension system. A mesh layer for electromagnetic shielding. A power isolation system doing some elaborate AC-DC-AC conversion (mechanically and/or electrically). Also, separate air handling systems to avoid connected duct work. And of course, there could be significant buffering and filtering via mass loading, shock absorbers, capacitor banks, chilled water tanks, etc.