I've seen something I've never seen in football on one of Frank's long runs, a 15, 20-yarder, where Bruce blocked his man and then Frank ran between Bruce and the defender he was blocking, and then came out the other side. It was really something to be seen. Almost like those car racers, when they drive through the smoke of an accident. He just went right through it. No, he didn't get touched. He was missing by the narrowest of margins. I can honestly say I've never seen a runner run between a blocker and a defender until now. Frank Gore."
Yesterday, 5-7-5-Niner posted a link in the comments to what appeared to be the run in question. The run came at the 10:56 mark of the 4th quarter, and I decided to put together a couple GIFs, as well as a screenshot. The run is at the 1:15 mark of this video.
Gore run in regular time
Gore run on replay
In looking back at the run, Miller engaged Johnson (No. 52), and it appears pushed him back a bit. This opened the hole for Gore to slip through. I think the second GIF provides the better look at what Gore might have been seeing on the run. As we can see, there was little to no space, and my guess is any other running back might have tried to kick the run outside to the left.
I don't know what Gore saw, but it could very well go to his trust that Bruce Miller would spring the hole. Whatever the case, Gore found the hole and was sprung for 14 yards.