• The episode title refers to a textbook that several other characters have admonished Dal for not reading this season, beginning in “Into the Breach, Part I”.
• Rok-Tahk catches Murf having a discussion with a silhouetted figure in the USS Voyager A’s astrometrics lab. Previously we’ve seen Silik speaking with the silhouetted Future Guy, beginning in ENT’s premiere, “Broken Bow”.
• Janeway speculates that the temporal shielding aboard the Infinity is what’s preventing Voyager A from being affected by the changes to the timeline caused by Chakotay and Adreek escaping aboard that USS Protostar in the previous episode. Temporal shielding was used to great effect during the USS Voyager’s conflict with the Krenim temporal weapon in “Year of Hell, Part II”.
• A chyron informs us the stardate 52 years in the future where the Protogies are stuck is, 112152.1.
• ”Then we send a hundred ships.” It was established in “Preludes” that the Vau N’Akat did indeed send 100 ships into the anomaly in pursuit of the Protostar.
• Zero descends into the Va’Lu’Rah pit carrying Dal and Maj’el in a manner not dissimilar to Spock carrying Kirk and Bones up the turbolift shaft with his hover boots in “Star Trek: The Final Frontier”.
• Dal claims to be able to feel that Gwyn is in pain while displaced from time. Dal has latent telepathic abilities from this proto-Organian genetics.
• ”I’m a doctor, not an exorcist.” The Doctor has uttered variations on Bones’ famous, “I’m a doctor, not a bricklayer,” in 13 prior instances.
• ”I came across a mission log where lieutenant Worf was able to jump between quantum timelines by generating an inverse warp field, siphoned from a temporal anomaly.” Maj’el relates the events of “Parallels”.
• Characters this season have chided Dal for not reading Temporal Mechanics 101, but, to be fair, the text appears to be a short video lesson, so none of them actually read it either.
• Doctor Erin MacDonald was first mentioned in the LDS episode, “First First Contact”, and seen in “Supernova, Part II”. She is based upon, and voiced by, Doctor Erin MacDonald, the science advisor who has worked on every modern Trek series thus far.
• Temporal Mechanics 101 has three examples of how to travel through time:
• Slingshot around the sun - “Tomorrow is Yesterday”, “Star Trek: The Voyage Home”, and “Penance”
• Get on the wrong side of a Q - “Tapestry”, “All Good Things…”, “Deathwish”, “Farewell”
• A wormhole - “Eye of the Needle”, “Into the Breach, Part II”
• Zero uses a chronitonic hypospray to temporarily prevent Gwyn from shifting between quantum realities. The Doctor did something similar in “Shattered” using a chroniton infused serum to bring Chakotay into temporal alignment after he was hit by a surge of temporal energy from an anomaly.
• The Doctor modified a phase discriminator to stabilize Gwyn. In “Timescape”, captain Picard, Data, Geordi, and Troi used phase discriminators to protect themselves from being trapped in a temporal fragment.