Permian, Midland Lee, and Midland High all ended with identical five and one records. The two teams that would go to the playoffs were determined by a coin toss. What is the irony in this?

The irony can be found in the fact that because of the coin toss, Coach Gaines and his team's presence in the playoffs will be determined by something he can't direct or control. The two teams will be chosen by the luck of a coin toss rather than the score of a game.