This is why teams have no problem running their running back into an impenetrable wall of defenders when they're trying to run out the clock. They're willing to exchange "failure" in terms of gaining any yardage for the minimization of risk and the depletion of the clock. This is all pretty simple. We've seen it a million times.
Now, you could argue that the team wasn't yet trying to kill the clock, and I would say that was a mistake on its part at the time. They sure should have been trying to kill the clock IMO, with a 72% chance of winning the game.