When camera pans to Rod Serling for his opening narration, you can very briefly see several crewmembers and some backstage equipment.
Producer William Froug rejected an extremely nervous young singer/actress auditioning for the part of Mary Rachel, and recalls thinking that "I'll probably kick myself. She'll probably be a big star." He turned out to be right on both counts. The aspiring young singer's name was Liza Minnelli.