***MASSIVE SPOILERS FOR PARASITE FOLLOW***
Even amidst a finale full of shocking moments, no scene in director Bong Joon-ho's Parasite comes close to the emotional gut punch of Mr. Kim stabbing Mr. Park. But what exactly led the mostly affable Mr. Kim to snap in such a brutal manner? The answer lies at Parasite's very core.
Parasite's main thrust revolves around the vast class dichotomy between rich people and poor people, as represented by two families––the Kims and the Parks. But more specifically, Parasite explores the deep conflicts that arise from the necessary dependence both classes have on one another in a society plagued by overwhelming stratification.
For the Kim family, who live at the bottom rung of society and are perpetually unemployed in spite of their varied talents and who scrape pizza boxes together to survive, latching onto the wealthy for job opportunities (by any means necessary) is their only opportunity to move up in the world. For the Park family, who live in such resplendent wealth that they can afford any luxury at a moment's notice, they still rely on the underclass to do their bidding––cooking, cleaning, driving, etc. And no matter how elaborately the Kims lie to the Parks, or how nice the Parks might act towards the Kims, the lopsided power dynamic is forever in favor of the Parks. After all, they hold the money, so they always hold the power.
While the Kims and the Parks enjoy relatively amicable relationships with their counterparts––Ki-woo and Da-hye are romantic with one another, Ki-jung is significantly older than and in an authoritative position to Da-song, and Chung-sook mainly stays out of Mrs. Park's way as the housekeeper––Mr. Kim's relationship to Mr. Park as his personal driver is more complicated. Mr. Park holds the most rigid views of class boundaries. He's amicable and friendly to Mr. Kim but quickly shifts to annoyance anytime he feels like Mr. Kim comes close to a conversational boundary (like mentioning Mr. Park's relationship with his wife). Unlike the other Kim/Park family relationships, the relationship between Mr. Park and Mr. Kim could be deemed subtly adversarial.
Of course, Mr. Kim doesn't just stab Mr. Park out of nowhere due to an ill-defined resentment. Mr. Park's murder stems from the build up of a few distinct events.
The first is Mr. Kim's body odor and the unfortunate circumstances that lead him to overhear Mr. Park complaining about it to Mrs. Park. After the mid-movie twist whereby the former housekeeper returns and the Kims lock her and her husband in the underground bunker, Mr. Kim finds himself trapped beneath a table, unbeknownst to Mr. and Mrs. Park while they canoodle on the sofa. During this time, Mr. Park vents about Mr. Kim's scent to his his wife, saying that when they're in the car together, he can't escape Mr. Kim's smell. "People who ride the subway have a special smell," he says.
Then comes the flood during which the Kim's basement apartment in the slums gets overrun by dirty sewage water. After spending the night sleeping in a gym with his children, the Kims need to return to the Parks for an impromptu Indian-themed children's party for Da-song. Immediately after losing everything he owns to the storm, Mr. Kim is forced to silently listen to Mrs. Park lightly muse about how fortunate it is that the rain cleared out the air before their party. Mr. Kim also notices Mrs. Park cover her nose at one point during the drive, likely exacerbating his bubbling anger at Mr. Park.
But the proverbial nail in the coffin comes when, during the party, the housekeeper's husband escapes the bunker and stabs Ki-jung. The shock of the scene causes Da-song to faint, and as Mr. Kim attends to his bleeding daughter, Mr. Park insists that he leave her to help take Da-song to safety. In fairness to Mr. Park, he doesn't realize that Mr. Kim is Ki-jung's father. But at the same time, Mr. Park's blatant disregard for the life of an employee stands in stark contrast to his heightened concern for his own son who's completely unwounded.
It is in this moment, tinted by unimaginable grief and sadness, that Mr. Kim's rage bubbles over––channeling the overwhelming rage of the underclass whose very lives are viewed as less than––and he stabs Mr. Park in the heart.
While Mr. Kim's actions may be brutal and wrong, it's easy to empathize with him. One can only take so much derision before snapping, and when faced with the cold reality of Mr. Park devaluing his daughter's life, Mr. Kim's snap seems natural. History has proven that when the uber-wealthy feed off the poor for so long without ever considering their hardships or humanity, violence will always be the outcome.