(only counting regulation time of course)
Those 4 drives accounted for exactly HALF of their 42 points prior to overtime. It's quite possible that Memphis still would've scored if they had longer fields, but it didn't help the BYU defense to be starting at the BYU 31.
Similar story with Boise (except it's a little less material), with 3 drives starting inside the BYU 36 for 17 points.