Lt. Ford tells Straker that the UFO has an E.T.T. (Estimated Trajectory Termination) at East Anglia. This is a region of the United Kingdom. Later, Ford narrows the E.T.T. to Norwich, a city within the East Anglia region.

On page 8, the UFO is described as descending to the ground like a sycamore seed. The common UFO in this series spins as it moves; sycamore seeds spin as they fall to the ground as well.

The photos on pages 8, 9, and 12 are from the episode "E.S.P.".

The UFO is damaged by cannon fire from a Mobile on page 9 and spews purple and black, then yellow and green, clouds of smoke. In "Identified", a UFO spews orange smoke after being struck by fire from Sky 1.

The narrative of this story explains that four UFOs have attempted to get past SHADO defenses in the past week, an unusually high number.

Page 10 suggests that, after a crash-landing, a UFO can destroy itself, leaving no trace of the vessel or its occupants.

The photo on pages 10-11 is a scene from "A Question of Priorities".

On page 12, Professor Stobart is reading up on the latest developments in transplant surgery and Freeman refers to him as a professor of medicine and advanced sparepart (artificial or transplanted organs) surgery. Since the professor was targeted for abduction by the aliens, it may be that his skills and knowledge of transplant surgery were wanted for making use of human organs in their bodies (which "Identified" suggests is the main reason for the aliens' visitations to Earth).