[Martin McFly]

Originally Posted by Taylor Mcknight

HERE IS THE PROOF....you shady hill-valleyian.

HERE'S MY REBUTTAL...you slacker!

I pulled up my copy on my laptop to check it out and while he does do a little hop and stop, he's not looking at Biff but rather the house. Just before the scene cuts to the DeLorean, he bends down slightly as though to squint at the house.

I always found that scene a little unusual anyway since he couldn't hear the DeLorean taking off nor see it with his peripheral vision. I suppose he was very interested in the house and the old saying, 'Out of sight, out of mind' applies here.