77 completely whiffed on his block on the edge. Kenny Cooper missed his block at the next level against Vic. In fairness to both, neither was a blown assignment, they knew what to do. 77 was just bad execution. Cooper's missed block was more of a function of Vic outrunning him to the spot and evading the block (although I supposed you could say Cooper took a bad angle). So really neither guy was Mills' to block, I think he was expecting to have to take on a corner or safety, and by the time he realized Vic was running free he was passed him and couldn't get back to block him. The other linemen downfield like Lee are how this play turns into a touchdown. If 77 and Cooper (or Mills) hit those blocks, the run is likely way down the field 20 yards. These extra linemen can then cause enough interference to prevent any remaining guys coming back across to help to have trouble stopping the play too.
When reviewing tape, I'm sure they'll point out to Mills that you have a main assignment, but you have to be aware of what else is going on too. Its these little things that turn 5 yard plays into 50 yard plays. Like someone pointed out above, regardless of the other missed blocks, had Mills picked up Vic even just to provide some interference, this could have been a long play.
This one play is a perfect illustration into the differences between a well humming machine and an okay one.
