What is it that upsets Montag when he is watching the program with the three women?

Montag pulls the switch to turn off the parlour wall when the images portrayed showed an arena of cars bashing into each other over and over again, while bodies flew through the air. He is upset by the brutality that entertains his wife and her friends.

Two minutes more and the room whipped out of town to the jet cars wildly circling an arena, bashing and backing up and bashing each other again. Montag saw a number of bodies fly in the air. "Millie, did you see that?" "I saw it, I saw it! " Montag reached inside the parlour wall and pulled the main switch.