Poker player Thomas got 8 and 7 while revealed cards have 9, 10, and a Jack. He just folds like that without hesitation on the $543K pot. Steve clearly doesn't have a good card because he even raised his hand in dismay, would you notice the faces and the actions of the poker players reflecting the cards they hold?
If you are Thomas and have just added more money to the pot, would you fold? We can't see his face though but I can just imagine how disappointing it would be to learn Steve just have KK
He probably thought and based on the situation as well that the best course of action is to fold, he will not get the bag, but he's still going to stay in the game, hence the lack of hesitation.