Roots: Mad Max 2. A cyborg dingo is (presumably) named after Kylie Minogue (nice!)
Technobabble: Greel's original time cabinet (actually Findecker's) features parallax synchrons and an intricate trionic lattice
Dialogue Triumphs: Tegan to the Doctor - "Will you stop holding time's hand for a minute? It can look after itself! It's bigger than you are"
"'Never' is probably the most annoying word in the universe" "Except in 'Never say die'?" "That's the spirit, Tegan!"
Kaori's last line: "I hope my service has been satisfactory... <BOOM>"
Continuity: The Doctor describes the vortex as ever-shifting. Turbulence in the Vortex is marked by a drop in quantum pressure, typical of an unstable energy source such as zygma energy. Zygma radiation is a notoriously tricky source of energy, being a double-nucleus particle; one half exists in the material universe, while the other mirror nucleus exists outside time and space altogether.
The war is between the Icelandic Alliance and the Supreme (Eastern) Alliance. The Filipino Army (which has a previous incarnation of the Doctor in its ranks) is stationed on the Siberian Floes. The Alaskans set up a neutron blockade on the Frozen Arctic. Warfare is formal with pre-announced moves, like chess
Nyssa and Turlough trained in Reykjavik for a year. Tegan's father's farm is just outside Toowoomba. She was schooled in Brisbane. She says Nyssa is her best friend.
The Doctor suggests hypnosis won't work on him. He says of "future lessons" taught at the Academy "Oh, you wouldn't believe..." and explains to Tegan that "sometimes" his knowledge of the future helps him stop thing from happening. He successfully mimics Findecker's voice over the air and contacts his previous incarnation in the Filipino army, directly calling an end to the Siege of Reykjavik.
Dr Sa Yy Findecker is a quantum physicist and a cyborg engineer of great achievements, according to the Doctor. His work, including the discovery of the double-nucleus particle, is the talk of faculty bars from Mars north to Goodweather III.
The Doctor has chocolate treats in his pockets.
Location: Earth, the 51st Century, including Brisbane Australia, Peking, China and Reykjavik, Iceland.
Future History: Transmat technology exists; 'trans-lag' is a side-effect. Air-skiing is a pursuit. The Earth is undergoing another Ice Age and the Siberian Floes are a future geographical feature. The Doctor tells Tegan that unlike the 51st century, Earth's 31st century was all space cities and monorails. Twenty centuries later a new ice age smothered Europe and the continents all the way down to Tasmania. Cyborgs are routine. It is a turbulent time, with global warfare over scarce resources. Brisbane is in the Dead Zone. The Earth Empire still exists, but Earth itself is no longer at its core. Guano dredgers sift the rings of Saturn. Earth Free Media is a pirate network and operate from a satellite station and are controlled by an Editorial department.
Links: The Talons of Weng-Chiang. The Doctor refers to Time Agents (also mentioned in the 'parent' story, though used here it's a ruse)
The Bottom Line: "Everything goes 'round..."
Platt does the almost unthinkable in combining a sequel, a prequel, and an origins story which is smart enough to not play things too straight (Greel himself being less the mad scientist and more the charismatic statesman is one of its best angles. This is better than his Mara sequel from two years back, and provided you can swallow the mad idea of Nyssa marrying Magnus Greel, you'll love it. In all, a ripping finale to the strongest Tegan/Nyssa/Turlough audio season yet.