Each tribute gets a chance on the last day of the training sessions to have a private session with the Gamemakers, during which they can show off their skills. This session allows the Gamemakers to score the tributes on a scale of 0-12, with 12 being a perfect score. The tributes are called in one at a time, beginning with District 1 and ending with District 12.
By the time Katniss goes in for her session, the Gamemakers are distracted eating and socializing, and do not pay attention to her as she demonstrates her skills. Katniss becomes angered and frustrated by their lack of attention. At the center of the buffet the Gamemakers are partaking in is a large pig. Katniss shoots and hits the apple in the pig's mouth, shocking the Gamemakers.
After leaving the training session, Katniss thinks about what she's done and fears that the Gamemakers will punish her or her family for her actions. She also fears that the Gamemakers will give her a low score, meaning she will receive no sponsors and no help during the Hunger Games. Haymitch agrees with this, noting that while they won't go after her or her family, they will try to make things purposefully more difficult for her in the arena during the games.
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She is afraid that she will be given a low score and will not receive any help from sponsers because of this. Katniss also fears that her loved ones will reap the repercussions of her actions in the training arena.
Because of her behavior towards the judges before the Hunger Games, Katniss fears that they will harm her family or District 12 as a whole. However, Haymitch ensured her that they wouldn't do that and that they would just make the Hunger Games harder for her, make it more difficult.
She is afraid because once she enters, all the gamemakers are casually eating and are distracted and even though she hit a perfect shot, they took no notice and when she got angry and shot an arrow towards the gamemakers and left she felt as if it was the wrong decision and gets worried they will come after or harm her family. Also if she receives a low score, she will receive less sponsors. Haymitch disagrees with this and instead believes they will simply make the Hunger Games harder.