• The episode opens in the office where Wesley took the Protogies at the end of “The Devourer of All Things, Part I”, which appears to be based on Gary Seven’s office from “Assignment: Earth”.
• Wesley confirms that it is not the actual office from “Assignment: Earth”, but a replica mimicking that office to train the Travellers’ field agents.
• The newspaper in the office has a headline reading “Apollo VII Launches.” There was an Apollo VII mission patch displayed behind the bar of the 602 Club in “First Flight”.
• The story of “Assignment: Earth” did feature a rocket launch, but that was for an orbital nuclear weapon platform, which Gary Seven was able to sabotage and detonate.
• When Wesley turns around the bookcase revealing a hidden computer identical to the Beta 5 computer as seen in “Assignment: Earth”
• Commander Tysess swears on the Wall of Heroes to protect Maj’el with his life. The Wall of Heroes was first mentioned in “United” when Shran said he would take Archer’s blood there after killing him in an honour duel.
• ”Fall back to the battle bridge!” The USS Voyager A is the only ship other than the USS Enterprise D to have a battle bridge mentioned in dialogue.
• Admiral Janeway shows up wearing a tank top, a look she first sported in “Macrocosam”.
• ”Tom Paris taught me that one.” Janeway and Paris spent a lot of time together during their time in the Delta Quadrant, particularly in the episodes “Time and Again”, and “Threshold”.
• The Voyager A’s shuttles are armed with quantum torpedoes. We’ve previously seen runabouts armed with micro-torpedoes, but this is the first shuttlecraft that has been explicitly said to be equipped with torpedoes of any sort.
• The shuttle is also able to survive the detonation of a full spread of quantum torpedoes at close range.
• ”Now, if you six would step under the modified Boreth crystals near the Orb of Time, I can get the quantum signature readings I need.” We learned in “Through the Valley of Shadows” that time crystals are a naturally occurring mineral on the Klingon monastery world of Boreth. The Cardassians returned Orb of Time to the Bajorans in the episode “Trials and Tribble-ations”.
• ”Fine, but Jankom’s still not sure this won’t scramble his genes like a Jiballian omelette.” Neelix claimed his seven-spice Jiballian omelette was famous in “Prototype”.
• Janeway recognizes Wesley despite the two never having met previously. This is because there’s only ever about seven people on any given Starfleet ship that do anything, so everyone in starfleet knows who they are. See: all of Star Trek.