Hans Olsen talked about this on 1280 this morning. BYU had just marched down the field with short slants across the middle and gashing runs of 10 and 14 yards. So what would make since at that point? Run it some more...especially if you only need 6 yards and have multiple downs to do it. You just gashed them for 10 and 14! So on reflection, those aren't really bad decisions.
Now, the option was a terrible decision...Kansas guarded that well all day. But that was an audible from Retzlaff based on something he saw. He misread it though. Terribly.
Then the last pass play was supposed to be a short slant across the middle. Sounds good. But the OLine got a false start, and then couldn't keep the pressure off Retzlaff, and an 11-yard play didn't have time to develop.