Coin wants to remain in power after the revolution, and if Katniss isn't going to support Coin's leadership, then Coin will use her in whatever way she can to give the rebellion momentum. For now, that might mean turning Katniss into a martyr. For everyone's safety, the crew sets up an around-the-clock guard on Peeta.
Katniss and President Coin didn't get along during their time in District 1, with Coin not believing that Katniss had what it took to lead a rebellion. Coin appeared to be a fervent supporter of the Rebellion, but she took advantage of the movement to further her own political interests.
Snow laughs after Katniss killed Coin because he enjoys the irony of the situation. He avoided the official execution ceremony, even though Panem's citizens still take their revenge on him, while Katniss ends up snatching away the victory and power that Coin thinks she has successfully secured.
However, she was slower to realize that the woman that had taken up the District revolution was more dangerous than she seemed. When President Snow told Katniss that it had been Coin who dropped bombs on Capitol children (and Prim), she finally understood—but there had been clues before this.
Using knowledge from the movie and the books, let's break down how The Hunger Games ends. Coin killed Prim to destroy Katniss because, as Boggs (Mahershala Ali) explains before his death, Katniss is her biggest threat to maintaining her power over Panem because of the influence Katniss has over the people.
What if Katniss Killed Snow Instead of Coin (Hunger Games Theory/ Fan Fiction)
Whose bomb killed Prim?
It later comes to light that the design of the bombs that killed Prim likely belonged to Gale. They looked like Capitol technology, yet that was exactly the purpose behind them; he created weapons that were meant to convince civilians that District 13 attacks were in fact perpetrated by the Capitol.
He did, technically, at least have a hand in it. But it wasn't intentional. Throughout the last book, Katniss is bothered that Gale seems to be getting closer to Coin and the district 13 higher ups. He also helped engineer the bombs that ended up killing Prim during the final battle.
She might even be worse than Snow considering the fact that Snow has honor, care for others like his family, and genuinely believed that the Hunger Games were for the greater good, while Coin simply continued the games as an act of vengeance and cared about nobody.
In the end, it is Gale's conviction in the necessity of sacrifice pitted against Katniss' moral incoherence that truly severs any relationship they had or could ever have. Primrose, Katniss' sister, is killed by a firebomb that may have been designed by Gale.
Haymitch Abernathy, the mentor for Katniss and Peeta in The Hunger Games, won his own Hunger Games through smart tactics and outsmarting his opponents. Winning the Hunger Games came at a great cost for Haymitch, as President Snow ordered the death of his family and girlfriend as punishment for his rebellion.
Snow can't stand to see a young woman betray a young man's affection—his view of what happened 65 years ago. And so he takes out his old, festering wound on Katniss.
According to Elizabeth Banks, who plays Effie Trinket, she and Haymitch's Woody Harrelson improvised their kiss scene in Mockingjay. Considering she's been adamant about the characters having some romantic connection, it only makes sense that they'd share a goodbye kiss. It's very on-brand for Effie, as well.
Despite being demented and megalomaniacal, Snow is also honest, and clings to his agreement with Katniss that they do not lie to one another, even if she doesn't. This also leads him to laugh mockingly when he is being executed, entertained by the sheer irony of the situation.
After winning the games, Snow forced Finnick into prostitution and sold his body to Capitol residents to gain their trust. Finnick only agreed to take part because Snow threatened to torture his loved ones. Even though he bedded several women throughout his time as a victor, Finnick's love for Annie remained true.
President Snow became evil because he's always been driven by the principle that, if a cause is just enough, then anything done in pursuit of it is justified. Unfortunately for the people of Panem, Snow believed the Capitol's dominance of the other districts was among the most just causes of all.
He chose Katniss because she was the stronger competitor, and to help her win he forced her to take advantage Peeta's romantic feelings for her. At the same time, however, he doesn't simply give up his fight against the Capitol, though a realist looking at the situation objectively might deem it hopeless.
She is only told that Tigris used to be a stylist for the Hunger Games, like Cinna, and that Snow fired her himself. Over the years, possibly to deal with the pain caused by her cousin's sadistic rise to power, Tigris tattooed and surgically altered her appearance so much that she looked more feline than human.
After Katniss' sister Prim was killed in a bomb drop orchestrated by Coin, Katniss showed up at Snow's execution, seemingly to kill him, but shot and killed Coin instead.
She remembers that they did indeed promise not to lie to each other anymore, and she realizes that Snow wasn't lying to her about Coin's role in the parachute bombing. He has no reason to lie to Katniss. His death is certain, but the future of the Capitol is not.
Before the Capitol battle, Gale had explained to Katniss his series of bombs designed to feed off human compassion: a small bomb would go off, and then when medical aid rushed in, a second bomb would go off, killing those people as well. Incidentally, it's this exact type of bomb that took Prim's life.
She was only 13 years old when she was killed in The Hunger Games: Mockingjay, and her youth only makes the tragedy that much harder for Katniss to bear after everything else she had suffered. Prim's death is a truly heartbreaking moment.
#CapCut Haymitch knew Katniss was planning something, she would never have voted for a symbolic Hunger Games and especially not for Prim. As soon as she did, he knew she was up to something and trusted her.
