Dave writes: I wonder what those people were looking at in the background.

So I cranked up the movie again and checked the scene. The folks in the room crowd close as the Kid checks, Lancey bets a thousand and gets string raised back by McQueen. The Kid is showing two black tens and two black aces while The Man has eight, nine, ten and queen of diamonds up.

The image in the lobby card must have been a seperate staging as the spectators are focused on the action in the movie scene. My guess... the catering truck was honking outside and the bit players were looking to dive into some of those New Orleans tacos.