In Spock's dream of a kal-if-fee fight with himself, the music is the same as in Amok Time (1967) when Spock fights with Kirk. The striking music, by composer Gerald Fried, is frequently cited as not only one of the best Star Trek (1966) scores, but one of the most outstanding television music scores ever.
The solar sail ship is similar to the Bajoran lightship flown by Benjamin and Jake Sisko in Explorers (1995).
In Enterprise Bingo, an unseen task was reprograming a medical tricorder to show the life signs of a Vulcan marsupial. This is a plot item from Life Line (2000). There Dr. Zimmerman, the creator of the EMH program is dying from an extremely rare and untreatable disease so the Doctor transmits his program back to the Alpha quadrant to treat him. But Zimmerman doesn't want to be treated by a first generation EMH (the program has has several versions since Voyager was lost) so at first he makes things difficult and plays pranks on the Doctor. In one of the pranks Zimmerman reprograms the Doctor's medical tricorder to register his life signs as a Vulcan marsupial. As the Voyager episode was set about 100 years after this one, it could be inferred that Dr. Zimmerman got the idea from Enterprise Bingo.
One of the names signed on the hull is "L. Ball" in honor of Star Trek (1966). Lucille Ball has a foundational role in the Star Trek franchise, as her production company, Desilu, produced Star Trek (1966), and she served as an uncredited executive producer on the series.
Title is a play on the TOS season 2 episode "Amok Time", which also features a kal-if-fee (Vulcan ritual challenge) brought about by T'Pring's refusal to marry Spock. However, that episode took place for real, whereas this episode features the challenge as Spock's dream/nightmare scenario.