It's not Army that the Big 12 teams needed to worry about. There was no way they were beating Notre Dame, just like there was no way that Navy was beating Notre Dame. The team they need to worry about is Tulane. Tulane was ranked behind only two Big 12 teams last week, and both of those two Big 12 teams lost today.
My guess is that after today Arizona State ends up ahead of Tulane in next week's poll. But they very well could be the only Big 12 team ahead of them. And they could easily lose at Arizona next weekend. The other two loss Big 12 teams are BYU, who is sinking like a rock, and Iowa State, who plays Kansas State next weekend. The Big 12 could easily have a championship game with a three loss team in it (and less likely could have two three loss teams in it). And if that three loss team wins, they are going to have a hard time getting a team in.