Warning: Big spoilers for the end of Orange Is the New Black season five below!
One of the biggest reasons Orange Is the New Black is so celebrated is for the way its writers take characters who might be one-dimensional caricatures in any other show and turn them into layered, diverse, and complex individuals reflective of the real people in the prison system today. In season five, corrections officer Desi Piscatella (Brad William Henke) gets somewhat the same treatment, and the way his storyline ends is unexpected, to say the least.
Throughout season four, Piscatella is the big villain (literally and figuratively) who seems to have one goal and one goal only while working at Litchfield Penitentiary: to make the inmates' lives a living hell. His brutal behavior is what pushes the Inmates over the edge in the second-to-last episode of season four, when their peaceful protest in the cafeteria leads to an all-out brawl that results in the tragic death of Poussey Washington (Samira Wiley). Early on in season five, Red (Kate Mulgrew) and Flores (Laura Gomez) take advantage of the guard-free prison during the riot and ransack Piscatella's office, hoping to find enough blackmail on him that will get him out of their lives forever. Their discovery leads to interesting revelations for all characters involved.
In Piscatella's office is the badge of a prisoner named Wes Driscoll (Charlie Barnett) from a maximum security prison Piscatella worked in years earlier, as well as a horrifying report of an inmate who burned alive under his watch. In Piscatella's backstory in episode 10, "The Reverse Midas Touch," it's revealed that he and Driscoll actually had a romantic relationship that was discovered by Driscoll's homophobic fellow inmates. They beat Driscoll badly, which is why Piscatella gets revenge by burning one of them to death in the prison showers. The flashback finally offers us a glimpse into what makes Piscatella tick (or in other words, why he's such an assh*le all the time), but unfortunately it comes a little too late to garner any real sympathy.
Despite the riot negotiations still being nailed down, Piscatella takes it upon himself to break into the prison solo and humiliate Red in front of her "family" (Nicky, Piper, Alex, etc.). He succeeds, tying them all up in a remote, empty room in the prison and torturing Red while everyone else can only watch (Alex does try to intervene, but Piscatella breaks her arm as retaliation). Fortunately, Freida Berlin (Dale Soules) saves the day by knocking out Piscatella with a homemade blow dart, and they drag him down to the bunker Frieda made in the abandoned pool in Litchfield's basement.
Meanwhile, a SWAT team begins raiding Litchfield to end the riot and violently rounds up all of the inmates using stun guns and rifles loaded with pepper bullets. As one SWAT team member explains to the other, you have to "shoot pepper bullets up" so that the case explodes above the target's head and rains down the chemical, otherwise getting hit head-on with one of the bullets can kill a person.
Down in the basement, Red seriously toys with the idea of killing Piscatella for everything he's put the inmates through before her inner humanity returns. She hears the SWAT team getting closer to their hideout in the hallways above, realizes it's all over, and lets him go. After apologizing, he heads upstairs into the hallway to greet the SWAT team so they can let him pass, but one of the guys gets spooked and fires his gun with pepper bullets. Even though he aims upwards, Piscatella is so tall that he gets the bullet directly to the face and immediately crumples to the ground covered in blood. Another officer comes over to check his pulse and tells the others Piscatella is dead.
It's a shocking way for him to go, to be sure, but after what he does in seasons four and five, it's hard to say he'll be missed.