Free was in pass protection and had Mathias Kiwanuka blocked pretty well, as linebacker Jacquian Williams blitzed on a rare occasion. But, instead of running at Romo and being picked up by a waiting DeMarco Murray, he ran away from the QB and right at Doug Free in a unique stunt idea. Free was knocked off his feet - as any tackle would be if blindsided by a sprinting linebacker while trying to block someone in a different direction and that left Murray to try to sort out what was happening and to pick up Kiwanuka which did not work out well. Kiwanuka pushed Murray aside and then put his helmet/shoulder pads right into Romo's ribs and looked like he did some considerable damage. You never see a WLB and a LDE stunt to that extent and there is no question that the element of surprise is what made that stunt work so well. They never blitz, and they definitely never blitz/stunt. Sometimes their scheme gets you, and they almost took out Romo in the process (medical exams pending).