Re: 7X11 The Crimson Horror(Grading/Discussion)(SPOILERS
It wasn't. Nor did it feature scarlet alien leeches.
But it did have a sociopath creating a group of 'perfect' people to repopulate the earth after dropping poison on it from a great height. And a damned near identical "rocket launch" scene with the good guys in the launch bay when the rocket goes up.
Pah! That's nothing like this episode.
“Wisdom comes from experience. Experience is often a result of lack of wisdom.”
― Terry Pratchett