Roots: As the Doctor explains, the title comes from the Welsh word for a city with many turnings, see also the Arthurian legend of Peredur (the revolving castle) and the legend of Theseus and the Minotaur (the original bull in a labyrinth). Wayland may take his name from the Germanic Daedalus-figure (as Caerdroia is a Celtic approximation of the labyrinth with minotaur it then follows that its creator would have an equal?) Labyrinth and the works of M C Escher. Charley refers to the alternative Doctors and their temperaments in terms of AA Milne's characters Tigger and Eeyore (see: Intertextuality), Alice in Wonderland, Monty Python's "Argument sketch" - the Doctor also obliquely refers to Monty Python and the Holy Grail (a flying rabbit) and Jurassic Park (an island with dinosaurs on it). The legend of Wayland the Smith. Charley mentions the writings of Edgar Allen Poe, particularly concerning evil twins (a vague doppelganger theme is in some of Poe's works including The Fall of the House of Usher and William Wilson)
Intertextuality: The Doctor's everlasting matches were first introduced in the novelisation Doctor Who and the Daleks - they have not yet appeared in the television series.
The Doctor's 'Tigger' personality may refer to a common fan description of the Eighth Doctor's more exuberant character.
Double Entendres: Charley and the 'irritable' Doctor: "And you be Eeyore.""-Are you implying something?"
"Where's C'rizz?" "-Up ahead, he's got some speed on him"
Dialogue Triumphs: "Of all the dangers I've faced I never thought I'd die of boredom."
Continuity: It becomes apparent that travel from one zone to the next in the Interzone is impossible unless the Doctor is conscious. The Doctor is able to affect his psychic connection with the Kro-ka, in essence blocking the creature from his thoughts. Among the Divergents' arsenal is a form of low-grade mind probe which the Kro'ka has stolen. The Kro'ka reveals that the Divergents borrowed many words from other cultures when those words are most apt. They are able to track the Doctor's movements through his dual heartbeats and the time residue that surrounded his body.
The Eutermesan Obelat is "indescribable", according to C'rizz (it seems to resemble a minotaur)
Gallifrey has a form of rabbit ('rounder' and more 'cuddly' than Earth versions) and a purple form of marlot which is not found anywhere else in the cosmos, whereas sunflowers are similarly unique to Earth.
The Doctor's feelings of "time sickness" seem to have originated from his being sensitive to time energy leaking through to the Interzone. He describes the sensation of being in a universe with time absent as like losing an arm. The Doctor once woke up in a field full of cows. Tigger appears to be his favourite character from Pooh Bear. He says sunflowers are unique to Earth.
Links: Everlasting matches (the Doctor uses his last one) and the Doctor's remark about sunflowers is a deliberate reference picked up in Terror Firma. The Doctor surmises that the Divergents are putting into action plans they made during previous encounters including memory editing (The Natural History of Fear) and personality duplication (The Twilight Kingdom) to discover his ability to operate the TARDIS.
Location: Caerdroia, part of the Divergent Universe's Interzone network.
The Bottom Line: "I may talk like a fool, but I always know what I am talking like a fool about."
Fun, if a little long. And it has the Kro'ka in it in a pre-adventure run around, but once the main story is reached (and the Doctor splits into his three aspects), things pick up considerably. McGann particularly seems to enjoy his time here, and the lighter side of C'rizz is appreciated. For an audio written by a prose author it's quite a visual story, and definitely one of the better Divergent tales.