watch that kid that goes in the store (around 1:15 into the scene) and then he comes back out, hes in on it.
also, its all pre planned, which makes it very possible to do. heres a few things to think about..
1) weird how there was a perfect piece of paper in the trash bin, aye?
2) those 2 people holding the paper, both work for him.
he didnt walk through glass, the glass was removed ;)