"The cylinder begins to rise. For maybe fifteen seconds, I’m in darkness and the I feel the metal plates pushing me out of the cylinder, into the open air. For a moment, my eyes are dazzled by the bright sunlight and I’m conscious only of a strong wind with the hopeful smell of pine trees."
Although in the movie Katniss doesn't actually tell Peeta it was all for the games - when they arrived back at district twelve and Katniss saw Gale and her family, Peeta takes one look at her and the emotion on his face is so powerful, he looks disappointed, like he's had the realization that is was all just for the games. (click on the picture)