While the exact word "Exposure" is sometimes used as a shorthand, other shows have high-stakes eighth episodes in their fourth seasons:
Though the episode is titled "Thanksgiving," the series name itself matches your topic. In this episode, the town of Cicely, Alaska, celebrates Thanksgiving with a unique tradition that includes throwing tomatoes at white people to symbolize historical grievances. [S4E8] Exposure
Remi faces literal physical to ZIP poisoning, which is rapidly deteriorating her mental state and causing hallucinations of her dead brother, Roman. Chicago Fire (S4E8): "When Tortoises Fly" While the exact word "Exposure" is sometimes used