How has katniss rebelled since arriving at the training center?

I agree with Katiepadre

After realizing the Gamemakers are only paying attention to a roasted pig that's just arrived at their table, Katniss fires an arrow straight toward the Gamemakers that skewers that apple in the pig's mouth.

Explanation:

I'm assuming you're referencing the first book, in which this takes place in Chapter 7.