10 More Horror Movies Where The Final Girl Was The Villain
7. Susan - Deep Blue Sea
Dr. Susan McCallister was featured throughout the marketing of Deep Blue Sea it very much gave the impression that she would be the lead. Combined with her crucial role at the beginning of the plot, and it was a natural expectation that McCallister would emerge as Deep Blue Sea's final girl.
However, that did not prove to be the case. Ultimately, she is the one responsible for all the deaths and carnage that unfolds in Deep Blue Sea, having been the mind behind the research program that genetically modified Mako Sharks unintentionally into killing machines.
Though she initially is unapologetic about her experiments, McCallister eventually destroys her research and starts her path of redemption. She even cuts her hand in order to prevent the sharks from escaping though this act leads to her death.
Initially, Susan was indeed the final girl of the film and she would have survived her noble act. However, because test audiences found the character to be too unsympathetic, she was killed in reshoots instead.