I know the guy at the top of the stairs yelling "Go!" at about 1:00 in the trailer. We've been extras a couple of times together and are FB friends. Nice guy - he's getting an acting career off the ground.
I had actually mentioned to him this summer that I hadn't seen any postings for TWD extras for Season 4 and he said it's almost all kept secret now because of the demand. I think his agent got him on the show.
My gimpy sciatica leg would've been great for this season.