Terminus: Part One

Stephen Gallagher found inspiration in Norse mythology, naming the Vanir after a lesser group of fertility gods. The individual Vanir also bore monikers redolent of the Norse culture: Bor was the father of Odin, head of the Norse pantheon; Sigurd was a great Norse hero (also known as Siegfried and Sivard Snarensvend); and Eirak was initially called Eirik, after a king of Norway and Northumbria also known as Eric Haraldsson or Eric Bloodaxe. Similarly, the Garm was named for a monstrous hellhound (also known as Garmr) who appears during the time of Ragnarok, the twilight of the Norse gods. Meanwhile, the term "lazar" was an archaic word for "leper", derived from the Biblical figure of Lazarus.

(Around 10m 40s) When the Doctor boards the spaceship and starts along the corridor, Nyssa's notebook is lying on the right near a doorway. However, when she dropped it (Around 9m 38s), it was in a more central position.