That's not how it works. The Big 12 rules, which I posted
here, lay out every instance in which a play is reviewable. According to those very same rules, anything not listed specifically as a reviewable play is not reviewable (according to Section 3, Article 4).
So can you just tell me, based on the rules I posted above, which one the refs last night used to review the clock?
They had PR hell last year because of the stupid tiebreaker rule, but they didn't just ignore the rule because it was inconvenient for Texas (though Mack Brown really tried to get them to).
As for Nebraska's ineptitude, I agree. But the fact that they were still in position to win the game despite that means that Texas clearly isn't good enough to play for the national championship.