What Keeps You Alive (2020) foreshadows Jackie's (Hannah Emily Anderson) fate several times in the movie and creates a huge plot hole in the process. As a matter of fact, the title itself foreshadows how Jackie will die—insulin can be seen as what keeps Jackie alive, and she ironically dies as a result of an injection that she believes to be insulin. The movie's plot hole is also related to Jackie's diabetes, and it might be somewhat obvious for those who know about the condition and insulin dependence. The worst thing about the plot hole is that it could have been avoided with a couple of small changes.
The film starts out with Jackie and Jules (Brittany Allen, Jigsaw) arriving at the cottage in the woods. As they settle into the house, Jackie asks Jules, "Hey, have you seen my insulin anywhere?" Jules replies, "Check your bag. Back pocket." The fact that Jackie relies on Jules to keep track of her insulin is the first in-film instance of foreshadowing her death, because it indicates carelessness on Jackie's part. Her carelessness with her diabetes is her weakness, and is ultimately a big factor in her death.
Jackie is shown injecting insulin for the first time when she is preparing tranquilizer darts to hunt Jules with. This foreshadows the fact that Jules uses both the darts and the insulin to beat Jackie at her own game. When Jules makes it back to the house the first time, she treats her injuries with the expertise of a professional, another foreshadowing of Jackie's fate. Jules uses her medical knowledge and her knowledge of Jackie's carelessness with her diabetes to kill Jackie.
In what is possibly the movie's most haunting scene, Jackie gives a speech that foreshadows her death once more. After Jackie kills Sarah (Martha MacIsaac) and Daniel (Joey Klein), she plays Beethoven's Moonlight Sonata on the piano over a montage of her cleaning blood under a blood tracking light. She says, "I'm free in all the ways you're not. You're trapped by emotions. Weighed down by guilt. Your conscience isn’t a source of strength, it's your Achilles heel." This speech is not only foreshadowing, but also ironic, since Jackie is ultimately killed because of her own Achilles heel, two actually—her insulin dependence and her arrogance, which like Achilles, blinded her to her own weakness.
What Keeps You Alive's Huge Plot Hole Explained
Jackie's death by peroxide-filled insulin needle is one of the great twists in What Keeps You Alive. However, the way it is portrayed is all wrong—Jackie is never shown measuring her blood sugar. This is the main way that diabetics know that they need to use insulin. Without measuring, there is no way to know how much insulin to use. After Jackie vomits and presumably believes herself to have high blood sugar (hyperglycemia), she does not measure her blood before injecting herself with the poisoned needle. Additionally, hyperglycemia doesn't generally have noticeable symptoms until it is dangerously high, which could require hospitalization, not just insulin. It also doesn't make sense for Jackie to be hyperglycemic after exerting herself so much in much in her second attempt to kill Jules. Strenuous activity usually causes low blood sugar (hypoglycemia), which would require a dose of sugar or a portion of food that increases blood sugar, not insulin.
To correct this plot hole, director Colin Minihan should have shown Jackie repeatedly measuring her blood throughout the film, since diabetics do this many times in a day. They should have shown at least once that she had high blood sugar because of a meal or a snack. They could have even had her mention it herself. The ending would have shown her feeling ill, measuring her blood, injecting the insulin, and then finding a note to watch the video. These small changes would leave all the great parts of What Keeps You Alive intact, but would also make it more authentic.