The concept of Plot Armor has existed forever and is something that any audience understands even if they don’t know that it has a name. In any given book, movie, tv show, or other form of story, the hero is guaranteed to survive at least until the end because the death of the hero would mean that the story could no longer progress any further. Only recently has this trope been subverted in popular culture by franchises like Game of Thrones, where no character is guaranteed to be safe.
Throughout John Carpenter’s The Thing, the largest source of tension is not the actual presence of the monster from outer space but the ever-looming uncertainty of where and who the monster is. At any point, any character on screen could be the Thing with no one the wiser, and no one would be able to figure it out because of how perfectly it can become a replica of the organisms it ingests.
There’s one exception to this though. At no point, throughout the entire film, does the audience ever really worry that MacReady, the main protagonist, is the Thing. Because of the established concept of Plot Armor, it would be impossible for MacReady to be The Thing and still act as the hero of the film.
One particularly dramatic scene in the movie illustrates this really well when you think about it, and that is the scene when MacReady and Nauls go out to search the shack together and Nauls discovers MacReady’s clothing bundled up in the furnace to be burned. In a panic at this apparent evidence that MacReady is no longer MacReady, he struggles back to the compound as fast as he can and cuts MacReady’s safety line to strand him in the blizzard, but MacReady manages to return and arms himself with a bundle of dynamite to keep the others from killing him. If this evidence had been found against any other character, both the other characters and the audience would be fully convinced that that character was the Thing. The evidence was irrefutable, except for the fact that it was against MacReady. The tension at this moment is not caused by the collective uncertainty by the characters and the audience of whether MacReady is the Thing or not, the tension is caused by the audience’s uncertainty of whether the other characters will trust MacReady or try to kill him. Paranoia has reached a peak in this scene and every character besides MacReady was non-essential to the plot and therefore expendable, so it was really up in the air how it could have progressed.
(There’s been some technical difficulty uploading to the forum, so hopefully at least this one posts.)