Voyage to the Bottom of the Sea - Season 4 - Eps 25: The Death Clock
"... but the Flying Sub's my baby!" Captain Crane to Chief Sharkey Seaview's reactor is running wild -- again. Without taking the time to don protective anti-radiation gear, Captain Crane runs into the Reactor Room to shut down the pile. An explosion renders him unconscious. Although treated in Sickbay with a special anti-radiation device, the Captain does not come out of his coma-like state. Doc can find no explanation. (Apparently, Doc hasn't read the script.) Corpsman Mallory has turned that life-saving device into a time-machine. Mallory is testing his fourth-dimension gadget on Crane before using it to enslave the entire world! A warped and insane Captain Crane from the future shoots and kills Admiral Nelson, because he believes the Admiral has held him back from achieving all he should have. Maybe he's paying Nelson back for the Krueger incident.
About Voyage to the Bottom of the Sea

Title: Voyage to the Bottom of the Sea
First Air Date: 1964-09-14
Last Air Date: 1968-03-31
Status: Ended
Rating: 7.7/10 (from 121 votes)
Language: EN
Seasons: 5
Total Episodes: 110
Network: ABC
Genres: Action & Adventure, Drama, Sci-Fi & Fantasy
Production Companies: Irwin Allen Productions, 20th Century Fox Television
Synopsis
Join the crew of the Seaview aboard their super high-tech submarine, where no mission is too dangerous and no threat is too deadly, be it enemy agents, mad scientists, deadly sea creatures, or impending nuclear disaster.
Cast

Richard Basehart
Adm. Harriman Nelson

David Hedison
Captain Crane

Terry Becker
Chief Sharkey

Del Monroe
Kowalski

Paul Trinka
Patterson

Richard Bull
Doctor

Robert Dowdell
Chip Morton