how does katniss show nobility?

Rue is not just another casualty of the games. She became Katniss's friend and ward. She defies the Capitol when she performs the noble act of decorating Rue's body with flowers.

I gather up an armful and come back to Rue's side. Slowly, one stem at a time. I decorate her body in the flowers. Covering the ugly wound. Wreathing her face. Weaving her hair with bright colors. Ch 18