Roots: The Odyssey (the legend of the original sirens), Babylon 5 ('Now it begins'), Das Boot, Badjelly the Witch (Maggie Stables' Ruthley), Red Dwarf ('You mean everyone's dead?'), Asimov's I, Robot and other novels (Pilot Azimendah's positronic brain, the implied laws of robotics), Shelley's 'Ozymandias' (the Pilot's name), Doctor Who Magazine's 1992 Winter Special comic strip 'Flashback' (temporal creature enslaved to further time technology, freed by the Doctor). Vampire legends, Holocaust concentration camp testimonies (the extermination of Time Lords in compounds, 'showers' that are not as they seem), plus news reports from the Hiroshima bombing of 1945 (Time Lords' telepathic impressions burned into the walls of the Capitol).
Intertextuality: The Temperon, Calfadoria, and the Drudgers come courtesy of the AudioVisual series with which Briggs was involved as an author. The Knights of Velyshaa and Drudgers feature once more in Big Finish's 'Dalek Empire' audio series.
Fluffs: In episode 1 following an explosion Sylvester McCoy seems to say 'I've lost my berries completely'. In episode 3 the word 'ship' is pronounced by Colin Baker and Sarah Mowatt with an almost silent 'p'.
Goofs: Three gunshots are fired inside a U-Boat with no observations made about the dangers of this to everyone on board. According to Big Finish's promotional blurb, the seventh Doctor is from a time immediately prior to 'Doctor Who', however the interior TARDIS noise and console switches sound the same as for the sixth Doctor's TARDIS in episode three. [perhaps he was in the middle of changing rooms?]
Technobabble: Cellular time disruption, temporal shock waves (mistaken for particle disruption fields causing cellular time disruption in organic life forms with notable exceptions), cross-brace fusion welds, and temporal thought projection all feature.
Double Entendres: 'Steady, girl, don't get overexcited.'
'Are we being watched?' 'No, why?'
'Be quiet, young lady, I haven't started on you yet.'
'For someone so short you're taking up a lot of room.'
Dialogue Disasters: 'You left out the bit about wiping my bottom.'
'The only place you can find Temperon particles-' '-is inside a Temperon!'
Dialogue Triumphs: 'Nobody is putting you out of my misery'
'A hole that big in a person usually indicates a zero chance of survival.'
Sancroff's closing speech.
'Do you know, talking to yourself is often thought to be the first sign of madness?' '-Ah yes, but a little madness helps, don't you think?'
'You're an android pilot with a spotless record. I'd trust you to fly me naked through a cheese grater.'
'Where's a handy ventilation duct when you need one?'
Continuity: The fifth Doctor's unseen companions Tegan and Turlough spend the adventure trapped inside the TARDIS. The sixth and seventh Doctors are travelling alone. The fifth Doctor is taken from somewhere between 'The Awakening' and 'Frontios'; the sixth Doctor from between the end of his trial and, according to Big Finish's website 'Time and the Rani', and the seventh Doctor from immediately prior to 'Doctor Who'.
On the unnamed planet, ion energy reveals the presence of alien life [it is otherwise uninhabited]. Artron energy reveals the presence of Time Lords and can also identify specific individuals, even acknowledging different incarnations of the same [perhaps it has a half-life]. Drudgers are hovering robots with mind scanners used to guard prisoners such as Sancroff. Such mind scans render the subject unconscious for around half an hour.
Coordinator Vansell is a member of the Celestial Intervention Agency (a comment from a Chancellery Guard at the story's end suggest that this is far from covert. The President (who's not a CIA member) knows what the CIA are up to). Vansell is able to sustain a temporal thought projection [i.e. shared consciousness] with humans (and androids with positronic brains) across time and space. His TARDIS is an unregistered modified Type 70. The 'current' Lord President is male. The Time Lords use a Time Chart, a monitoring device that maps events.
The Temperon, a 'distant cousin' of the Chronovores, is a legendary creature known to the Time Lords and the Sirens of Time. It can travel in time and space, and it might be inferred that this is also a creature of Gallifreyan lore (the sixth and seventh Doctors quote the same rhyme 'the Temperon flows its way through the oceans of time, serene, sublime...'. Its particles can be used in time experiments and can adhere to (and thus travel the Vortex upon) TARDIS outer shells and even penetrate them. Temperons may revise temporal anomalies and change the course of history retrospectively (as one does at the end of this story).
The Sirens are another time-faring race who feed upon time distortions and paradoxes. They cannot cause such disruption, but may only lure other races to cause it and thus feed off the resulting chaos. It is implied that this is not through lack of ability but, like the Guardians, they cannot be seen to be interfering with the fabric of time. To answer their call twice is to be enslaved to them eternally.
The star cruiser Edifice has a crew of 500 and supports 5000 passengers. It has reserve chemical fuel tanks and (it is implied) an internal combustion [backup] engine. Its bulkheads are of Hadene LeStrade design.Aboard is a conference of Galactic Wonders Commission delegates (of which the Kurgon System is host) in order that the Kurgon Wonder (thought to be a gaseous anomaly 215 million 'metrons' wide) can be entered as a Galactic Wonder [see 'Death to the Daleks'].
The Knights of Velyshaa once had a large empire before they were toppled in a great war against Earth in 3562. Their leader, Sancroff, was sentenced to exile by the War Crimes Tribunal and would have been executed by Calfadorian bio-assassins had the seventh Doctor not intervened. They thus achieved the Second Empire which enslaved the Temperon, realised temporal technology and vanquished the Time Lords. The Knights' temporal experiment to create a time travelling spacecraft was halted by the Temperon, freezing them all in time until the sixth Doctor freed them. Due to mutations from exposue to Temperon particles they have become a parasitic race, requiring 'revitalisation' from the life forces of other species to nourish the withered and decaying bodies under their 'mediaeval' armour. Their weaponry inhibits regeneration.
The fifth Doctor is unable to prevent the sinking of the Lusitania. Had he done so, a petty criminal by the name of Eric Charles Vincent would have lived to kill Alexander Fleming in a botched robbery. With penicillin having not been discovered, the world would have fallen prey to meningitis and pneumonia in 1956, with the survivors never developing a space programme, ultimately encountering and defeating the Second Velyshaan Empire.
Time distortion can be seen and travels in 'shards'. The Doctor has a certain tolerance to it, as do the Sirens. TARDISes have a time core [Vansell's does - in 'Sword of Orion' the Doctor mentions one in his as well]. Once again, the Doctor is mistaken for, and poses as, a delegate at an intergalactic conference.
According to the sixth Doctor, each of his incarnations displays a certain characteristic of his personality more strongly that the others. 'His' is pragmatism.
Links: 'The Time Monster' (Chronovores), 'The Three Doctors' ('Contact!'), 'Marco Polo' (The sixth Doctor recalls climbing the Himalayas), 'Death to the Daleks' (Wonders of the Universe), 'Logopolis' et al. (the Cloister Bell), 'The Deadly Assassin' (artron energy).
Untelevised Adventures: The sixth Doctor recognises the Edifice's construction, having seen similar ships. He (or one of his predecessors) knew Lastrade.
Location: An unnamed planet sometime after 3762; the U-Boat U-20 in the Atlantic Ocean (en route to New York from Liverpool) shortly before the sinking of the Lusitania [7 May 1915], the star cruiser Edifice in an unspecified time zone in the Kurgon System, Gallifrey (the Capitol, including the Panopticon).
The Bottom Line: 'So this is how things turn out for me?'
The first of the long-anticipated audio dramas is something of a mixed bag. While the fifth and sixth Doctors' segments maintain the listener's interest, the all-important first (seventh Doctor's) segment is unfortunately rather dull. And yet again we have a 'Gallifrey under siege' tale. Despite having a rushed ending, 'The Sirens of Time' is a much better example of what can be achieved with Doctor Who on audio that earlier radio attempts. In all a highly entertaining experience. With three of the surviving TV Doctors, new monsters and an arsenal of sound effects, there's something here for everyone.
There is sufficient evidence to support that each multi-Doctor adventures 'belong' to the lattermost Doctor. However, 'The Sirens of Time' cannot 'belong' to the seventh Doctor or the sixth in view of the events in [the later audio tape] 'The Apocalypse Element' specifically with regard to the death in that adventure of the President. And in light of the later-produced stories 'Shada', 'Neverland', and 'Zagreus', it is clear to us now that the Big Finish Gallifrey is set within the eighth Doctor's time stream. This now means that all three of the Doctors featured in 'The Sirens of Time' are taken to Gallifrey in their own futures (and which now makes sense of Romana's cryptic comment in 'The Apocalypse Element' that the sixth Doctor is the 'wrong' Doctor).