Watched a WPT final on TV. Final head-to-head, Player A holds As5c. Player B holds 2c2s. Player A goes all-in; Player B calls. The flop throws up an Ace, 8 and 9. The turn throws up a 2. Both players immediately stand up and shake hands, and commentators say "game over". But why? Couldn't the river have brought up a third Ace?