http://www.nfl.com/videos?videoId=09000d5d80d52ce8 Watch around 20 seconds in, if Wayne Hunter makes the block BF goes all the way.
I remember watching the replay and saw Wayne slow up after favre got about 10 yards down field, THEN tried to speed back up. It's true if he would of ran with #4 the whole way, he most likely makes the block that allows favre to run it in. Still - the fact favre had a 25 yard run is impressive enough. =)