I never saw many of the fourth season TZ episodes, probably because the hour length made them more expensive (and therefore less likely) to be re-run. But I got a complete TZ boxseet a while back, and have watched some.
An interesting one is “Passage on the Lady Anne”:
[spoiler]A young American couple books eastward Transatlantic passage on a mysterious 50+ years-old English luxury cruise ship. They soon observe that all the other passengers are English, and over 75 years old. After some cryptic hints, they learn that the cruise line plans to decommission the Lady Anne, and the passengers (all long-time repeat customers who’ve become very close over the decades) have decided to ride out to sea, and go down with the ship when the crew (who are also old, and close to the passengers) deliberately sinks it.
The motivation for this swan song is the elderly passengers feeling out of touch with modern, fast-paced ways (and transportation), which dovetails with the American husband’s workaholism and impatience, which he moderates over the course of the voyage.
At the end, the young American couple are informed that they will be spared: their rescue has been summoned, and they are put on a lifeboat with supplies (to include an RF beacon).[/spoiler]One thing I wanted to say: I’d always thought that the only two TZ episodes with no supernatural phenomena were “Where Is Everybody?” and “The Silence”.
But “Passage on the Lady Anne” would seem to be another, unless I’m missing something.