This episode omits the opening theme.

Linda appears to be driving a red Porsche 914 Targa convertible.

At the beginning of the episode, Linda is wearing the same sexy, red leather dress worn by Anne Stone in "The Sound of Silence".

Straker tells Clark that he's from Boston. Presuming this is the truth, this is the first we've heard of Straker's place of origin other than being American.

At 10:44 on the DVD, Ayhea tells Foster that Straker's car has sent an alert about 3 km from Junction 14. I've not been able to find what might be referred to as Junction 14 in the London area.

In this episode, Straker mentions Skydiver 3 (Foster also mentions "all Skydivers" and Colonel Lake later mentions Sky 4), seeming to confirm that there are multiple Skydiver vessels. We also see Skydiver 3 here, though only Skydiver 1 is ever seen in any other episode of the series.

How is Clark able to tear through a chain-link fence with a karate chop with his bare hand?! Even mind-controlled by aliens, their are limits to the human body!

As Clark walks through the torn open fence at 14:58 on the DVD, a shadow passes alongside the fence from the interior side; it must have been a member of the production crew moving out of the way before the camera pans over in that direction.

At 19:57 on the DVD, a number of earth-moving vehicles manufactured by Caterpillar are seen.

At 21:28 on the DVD, there appears to be an issue of Life magazine on the coffee table behind Linda.

In the executive's office, the scene outside the window at 21:32 on the DVD is the same one seen through Collins' apartment window in "The Man Who Came Back".

Captain Lauritzen's apartment appears to simply be a redress of Collins' apartment set from "The Man Who Came Back".

Mason seemingly absorbs the skin of the fingertips of Captain Lauritzen's left hand on his right one, leaving bloody patches on Lauritzen's fingers. But this would seemingly create reversed fingerprints (and on the wrong hand!), so it shouldn't work on SHADO's computer scan; yet it does!

In this episode, Skydiver 3 is seen docked at an underground submarine facility.

At 24:27 on the DVD, Linda is clearly rolling down her car window manually, yet it makes an electric hum as if it was operating electronically!

At 29:00 on the DVD, indentations from Mason's fingers are seen in the steel door he forced open. But they weren't there a few seconds earlier when he actually forced the door open and squeezed through!

At 34:01 on the DVD, why did Linda lock the doors of her car such that she has to unlock them now as she leaves her apartment building? The windows are clearly fully open! Notice that she places her left hand around the open windowsill of the door.

Linda's license plate is BMW 189. It looks more like a California license plate of the time (with the "California" covered up) than a British one!

The apartment building of Linda Simmons appears to be called Albion (which is an ancient name for the island of Great Britain).

Straker implies that a UFO left in Earth's atmosphere for more than about 48 hours will start to disintegrate.

Were these shots (at 41:47 and 47:53) intentional?!

In SHADO HQ at 43:41 on the DVD, it can be seen that there is no corridor to the right or left for Foster to be walking from!

At 44:24 on the DVD, Linda is wearing the same boots Jo Fraser was wearing in "The Responsibility Seat".

UNANSWERED QUESTIONS

The aliens have attempted to have Straker killed several times in the series, so why doesn't Clark, while under their thrall, kill him when he has the chance? He just leaves Straker unconscious in his car with a message that SHADO must cease a number of its operations. 

How did Linda Simmons withstand the gunshots fired by the guard in her holding room at SHADO HQ?!

MEMORABLE DIALOG

voice print identification.wav

some superhuman force.wav

a psychobomb.wav

the ability to call on the potential of the entire universe.wav

surrender SHADO.wav