The fake radio station the team pretends to transmit from is identified as "KGL Fresno". Fresno is approximately 4 hours / 200 miles away from San Francisco. A radio station in Fresno could never have been picked up in San Francisco (much less from a basement).
The taped voice commits a blooper in Jim's message. After mentioning the scientists as Edward Stoner and Wilson Cardel, the voice identifies the two married couples as "the Wilsons and the Cardels" instead of as "the Stoners and the Cardels."
Dr. Cardel: Wasn't using gas risky?
Rollin: What gas?
Dr. Cardel: You mean, it wasn't really gas?
Jim: Well, it was as real as the earthquake.
This episode earned an Emmy nomination for Joseph Sorokin for Sound Editing.