It was one of the best scenes in the movie. Why did she do this? It's not as random as it may appear in the film. In the book, Peeta explains Johanna does this to see Katniss' reaction.
Johanna remains in the Capitol for quite a while, and she and Peeta are tortured for information concerning District 13 and the mockingjay rebellion. While in the Capitol, Johanna's entire head is shaved, making her bald. Johanna after she is rescued from the Capitol.
In the case of Johanna, they each hated each other because that was what the Capitol had taught them to do. They were from competing Districts, and the idea of the Games was to keep the lesser citizens of Panem distrustful of one another and unwilling to form alliances (or raise arms in war).
Even though the two were now allies, they still didn't trust each other. During the escape from the arena at the end of these Hunger Games, Johanna 'attacked' Katniss for the purpose of removing a tracking device from her arm, then lead Brutus and Enobaria, the District 2 tributes, away from Katniss.
The Hunger Games: Catching Fire (5/12) Movie CLIP - Johanna in the Elevator (2013) HD
Is Johanna addicted to morphling?
Johanna Mason developed an addiction to morphling while hospitalized in District 13 for the torture she endured in the Capitol. When she was weaned off, she instead dipped into Katniss's supply.
Since Haymitch Abernathy's family was killed after his Games, and he mentioned Johanna's name when he spoke about being held up as an example to younger victors, it's commonly theorized that Johanna refused to be sex trafficked as Finnick had been, so her loved ones were killed in retaliation.
Ever since their first meeting in the elevator, Johanna Mason has had her eye on Peeta. Even though she came off as cold and distant, she was never afraid to show her admiration for Peeta. In that same scene in The Hunger Games: Catching Fire, Johanna asked Peeta how he felt now that everyone wanted to sleep with him.
The female Morphling, however, appears almost coincidentally, and Peeta even mentions that they don't know her real name. Given that she is willing to make the ultimate sacrifice to protect Peeta, it's safe to assume that the Morphling was committed to the rebel cause.
Johanna and Katniss take the first watch that night. Johanna tells her that Mags was Finnick's mentor and half of his family. She also tells her that she was with Wiress and Beetee because of Katniss. According to Johanna, Haymitch said if she wanted to ally with Katniss, she'd have to have Wiress and Beetee with her.
Who has the most brutal death in the Hunger Games?
Glimmer. Alongside Marvel, Glimmer was a career tribute from District 1 with a tendency for brutality and arrogance. When Katniss is stuck in a tree waiting for the career tributes to give up, she receives the most brutal death in the Hunger Games franchise.
Peeta used the dyes to paint a picture of Rue after Katniss covered her with flowers when she died. He says he wants to hold them accountable for killing Rue, and Effie tells him that that kind of thinking is forbidden. Katniss then tells the team she hung a dummy of Seneca Crane.
Johanna pretended to kill Katniss and dug out her tracker. She then led Brutus and Enobaria away from Katniss and they followed Johanna. Johanna was captured by the Capitol but was rescued by District 13.
She decides to take the two of them out with her arrows, but then remembers Haymitch's words before she left for the Games. Haymitch had told her to remember who the enemy is, and she soon realizes who the true enemy is. It isn't Enobaria, Finnick, or Johanna. Instead, it is the Capitol, who created these Games.
While in hiding none of the other tributes could find her and there was an earthquake that caused floods in the arena. Since Annie was from district four where fishing is the primary work, she was an excellent swimmer which allowed her to survive the flood and the hunger games.
Chia Mags kisses Finnick on the mouth to briefly let him know that this is the last time she will see him. It's her way of saying "Goodbye" but in a more affectionate way.
Yes, Katniss did develop an addiction to the morphling, on account of constantly being sedated with it, however, I wouldn't say that she was an addict. An addict is someone who goes to a substance (or whatever their 'poison' may be) under their own mind.
Finnick rushes to resuscitate him as he knows he needs Peeta alive to keep Katniss going. Another clue that he is in on the rebel plan comes when Katniss is about to kill him with her arrow, and he tells her, "remember who the real enemy is," which is something Haymitch said to her before the games.
Their relationship was all friends. They trusted each other, but that doesn't mean they had romantic feelings for each other. Plus, Cinna's too old for Katniss.
Katniss made the choice to build her future with Peeta. If she didn't love him, she wouldn't have made that choice. Katniss made her whole world about getting the people she cared about to the next day, her choice to survive with Peeta proves her love for him.
Later, the two learn President Snow considered their actions to be an act of rebellion against the Capitol. After their last interview, in which the two continue to affect their romantic feelings for one another, Peeta comes to the realization Katniss has staged her love for him all along.
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.
Katniss, drugged and recovering in District 13, dreams of Peeta. She wakes to find Johanna Mason stealing Katniss's morphling drip. Katniss had been spared serious injury thanks to Cinna's armored Mockingjay costume.
During an interview Katniss and Finnick shot to distract the Capitol from the rescue team, Finnick reveals President Snow kills his enemies and allies who can become threats to him. He also reveals that Snow forced Finnick into sex trafficking, selling his body to wealthy Capitol citizens for high prices.
