So Scarlet doesn't sense the Mysterons anymore? Hmm. It was nice of the show to tell us.

It's a pity that Alan Pattillo didn't write any more Scarlet eps - this is a masterpiece!

One of the caterpillar tracks on the SPV moves as Blue backs away from the castle.

Symphony: 'Have you seen Captain Scarlet, Morton?'
Morton: 'No miss. I've looked everywhere.'

Hang on a mo. Scarlet was imprisoned in the dungeons. So you DIDN'T look everywhere you silly little man.

On his first line, the Delta attendant is played by Martin King. On his second line, Jeremy Wilkin plays him.

Let's see. We know that the Mysterons can reconstruct people and things after they have destroyed them, right?

Melody reports that she thought that she saw the plane ahead of her struck by lightning. The plane is out of touch for several minutes. No one thinks that this is worth looking into BEFORE they send all these valuable people off together? How about just a quick scan with a Mysteron detector? Would have shortened the episode, but hey, you can't have everything.

Morton mentioned that the castle wasn't a tourist attraction because the current fad was for castle ruins. He'll really be raking the money in now!

There is a bizarre shot in this episode. When the newly-Mysteronised XQR lands on Cloudbase, the camera zooms in on Holt to ominous music. Hang on...shouldn't the camera have zoomed in on Goddard, seeing as he was the main player?

I know...I was expecting the cameraman to suddenly shift over to Goddard at the end, in a sort of 'woops' moment.

Down in the dungeon, when they show the "live" shot of Captain Scarlet's hand, his fingers are just millimeters away from the spear. When they draw back for the long shows, it's obvious that the spear is totally out of reach of Scarlet's hand.

Does it seem likely that there would be a grating in the ceiling of the dungeon that opens right into a main hall of the castle? Wouldn't the screams and curses of prisoners disturb the inhabitants of the castle? That's why dungeons are way down below, after all.

Captain Blue must not have much confidence in his shooting ability. He got Goddard with the first shot, then proceeded to wreck the castle (and probably bury Captain Scarlet) with two more hits.

Col. White needs to be a little more laid back. Captain Scarlet's dry statement, "I guess that I'm indestructible," could be taken as a dead-pan joke, but the way that Col. White hastily jumped in must have sounded odd to the listener.