Katniss speculates that Coin deliberately sent Prim to die in the Capitol bombing in order to fully gain her trust, but it's never outright confirmed or denied.
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.
Peeta is held back while the other rebels are sent to attack the Capitol, but he is later sent to join them as a member of Katniss's group of sharpshooters, which Katniss suspects is because President Coin sees her as a political rival and wants Peeta to kill her.
Katniss was the symbol of Coin's rebellion in Mockingjay - Part 2 — the movie's mythologized, titular hero who starred in propaganda films to fuel the effort's fire. Coin had no choice but to work with Katniss, but in the end, the poster girl turns on her anyway in an unforeseen act of defiance.
The squadron eventually comes to the conclusion that President Coin had deliberately sent Peeta to Katniss' squad in hopes that he will go mad and kill her because Coin sees Katniss as a political rival.
The Life of President Alma Coin: The Real Villain of the Story (Hunger Games Explained)
Why does Plutarch smile when coin dies?
It is likely that he is a relative of Hilarius Heavensbee. In the Mockingjay - Part 2, Plutarch appears to smile as he looks at Coin's dead body, suggesting that he approved of her death.
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.
Katniss searches his eyes for signs of emotion but only finds amusement in them. 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.
Peeta decides, though, that he will go out on his own to act as a diversion in case Katniss and the others need it. Gale gives Peeta his nightlock pill in case Peeta's captured. They leave early in the morning, bundled up and styled by Tigris. Cressida and Pollux go first, leading the way to the City Circle.
That said, it was stated that an emergency election took place after Katniss assassinated Coin. Commander Paylor, a vital leader in the Second Rebellion from District 8 was elected as Panem's new president.
Such encouragement is what Katniss needs as she continues her development as the Mockingjay. When Boggs tells her not to trust “them,” he is possibly referring to Coin, who Boggs has already said is afraid of Katniss because Katniss hasn't given Coin a full-hearted endorsement.
According to the star behind Effie, Elizabeth Banks, she and Haymitch's Woody Harrelson improvised the scene. 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.
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.
Prim was among the medics who arrived to treat the victims. Unfortunately, a second batch of bombs were set off, with Prim being killed in the explosions.
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.
If Katniss chose to kill Snow instead, Coin would have still been as tyrannical as him and possibly even worse. Katniss herself realizes this and shoots Coin instead of Snow during his execution. Unlike the main villain Coriolanus Snow, she has no redeeming qualities, care for others, or tragedy.
Katniss's focus on survival and her family's safety prevented her from fully considering romance, but her feelings for Peeta and Gale diverged in the end. Katniss ultimately chose Peeta because he understood her trauma and she didn't want to lose him, proving her love for him.
He has betrayed her and is betraying all of District 12 by buddying up with the Careers, whom she calls the "Capitol's lapdogs." She decides that if the Careers don't kill him, she'd be more than happy to. Then, she wonders why Peeta hasn't told them about her bow and arrow skills yet.
After reading the book and watching the film, it seems clear that Lucy Gray realizes Snow was responsible for the death of his friend Sejanus Plinth (Josh Andrés Rivera). If Snow could sell his best friend down the river for personal gain, it was only a matter of time until he did the same with her.
In the end, she goes as far as to bomb children and hold a new Hunger Games just to secure her victory. It is still possible that she genuinely wants to make Panem a better place, but her methods become inhumane. Coin feels threatened by Katniss' rebellious nature.
Why did Peeta stop Katniss from eating the Nightlock?
3) He stops her taking the nightlock pill after she kills Coin. He knew her well enough to know that not only would she try to kill Coin but that she would then try to kill herself straight after with the nightlock pill.
President Coin called together all the remaining Hunger Games victors and asked them to vote on her idea to reinstate the Games—this time using Capitol children. It became clear then that Coin had the same mentality as Snow. To her, children were a tool to be used against those that loved them.
In the end, Katniss and Gale grew apart, as many childhood friends and young loves do. She needed something different in her life, and with Gale's link to Primrose's death, Katniss found a reason to cut ties. If Katniss ever wanted to find comfort again, she knew she had to return to Peeta for the long term.
He chose his ideals over Katniss. So Gale is the classic 'hot-headed-hero' character, a ruthless visionary. Good and bad are very narrow words. But considering everything, Gale Hawthorne was probably the good guy.
