As the hovercraft goes out of control near the end of the ep, keep watching the right hand side of the picture on the modelshots. At the beginning of one, a massive wire can be seen coiling up and down as if from a sdden tug on the model

Why do Machin and Johnson swap seats for their second hovercraft trip.

When Stone calls Johnson back to have a private chat, Johnson replies with Machin's voice.

I really would like to see what IQ rating Captain Blue has, from such dialogue gems as:

Stone : The cadets are looking forward to your lectures.
Scarlet : We're always glad to help in any we can.
Blue : IN ANY WAY, Major.

So, great. Blue's gone and blown their secret plan in the first thing he says.

'I might be the traitor, or anyone on the base!'

So, multiple personalities then, eh? Not happy with being just himself, has to be everyone else too? Greedy.

>>Why do Machin and Johnson swap seats for their second hovercraft trip.<<
Johnson probably doesn't trust Machin at the controls, but it's strange that they have swapped seats and so has the switch that activates the boost as Machin tries the switch on both patrols.

And what did happen to Machin?
Was he put on trial for his actions, I mean he was risking Johnson's, Scarlet's, Blue's and even his own life by holding them at gun point in a runaway hovercraft that was going to blow up.

And its also screamingly obvious he started the fire.

Johnson calls Stone 'Sloane' at one point.

Why are hovercraft pilot seatbelt buckles at the waist, but passenger buckles are around the chest?

They shrug off that fire awfully lightly at the end. It looked like a pile of clothes burning. I don't think that military men, trained to neatness, would leave their clothes in a pile on the floor, especially when they are more or less "on duty" at all times during this crisis. And what started the burning? Scarlet or Blue might smoke off duty (especially Scarlet, since he doesn't have to worry about lung cancer anymore!) but they would hardly toss their cigarette stubs on the floor of their room. And it was hardly a situation for romantic candlelight....

BTW, is it really correct to refer to an inanimate object as a "traitor"? Doesn't "traitor" and "treason" imply a concious betrayal?

Apparently, in the original storyline, the little valve was not altered by the Mysterons--it just got affected by the Australian heat.

When they show Captain Scarlet tugging at the control box, in the long shot, they show him also pulling on a wire by the box. In the "live" closeup, both of his hands are on the box.