"Explosive" I believe means runs of 12 yards or more. While they weren't getting 12 yards, watching Q4 it felt to me like they got a LOT of 7-8-9 yard runs. Not enough to trigger the "explosive" run category, but more than enough to march down the field like a hot knife through melted butter. And the offense not being able to hold the ball a bit longer themselves certainly played into that - it sure didn't help the run defense that they were out there for what seemed like hours, then after Chicago scored, they barely made it back to the bench before they had to go out again...