Revealing mistake: When Thunderbird 2 returns to its hangar at Tracy Island, smoke can be seen flowing back down into units inside the hangar, revealing that this is simply reversed footage of the regular Thunderbird 2 launch sequence.
Thunderbirds (1964)
1 revealing mistake in Security Hazard - chronological order
Starring: David Graham, Ray Barrett, Peter Dyneley, Shane Rimmer
Audio problem: As John and Gordon are fitting the new component on Thunderbird 5, John says, "It looks like we'll be another two hours before we're back in business. In the meantime, International Rescue is non-operational." But he is voiced by David Graham, not Ray Barrett.
Trivia: Jeff Tracy's five sons were named after Mercury astronauts - Scott Carpenter, Virgil Grissom, Alan Shephard, Gordon Cooper and John Glenn.