The corridor that Leonard Nimoy goes through that has the ultrasonic deterrent is a redecorated section of the USS Enterprise of Star Trek (1966). Mr. Nimoy has traversed this corridor many times.
This show is similar to last season's The Vault (1969), in which Nehemiah Persoff's character was again the Finance Minister and the main adversary. In "The Vault", his character's plan was for personal gain by ousting his country's president by discrediting him, and assuming power. In this show, his character's intent is to wreck the Bahkan treasury to cause an overthrow that will destabilize the region.
The graphic showing the wave pattern of the deadly sonic security system is a re-use of the voice print graphic from the previous season's [link=tt0649285 & The Bunker: Part 2 (1969).
Per the title Fool's Gold (1969), the natural mineral is pyrite, an iron sulfide with the formula FeS2.