I had a good time with Korny trying to glitch out of the map in the Alpha and decided to give it another shot the other day. Get across the roof of the building with the satellite dish in Old Russia and it's possible to phase through the floor of the map.

It was easier to get up on that initial ledge in the Alpha but there was a sort of rubber-band barrier covering the whole thing that eventually pushed you off the roof unless you summoned a Sparrow and just sat there. The barrier has been mostly replaced with a kill timer in the beta so it's possible to charge across to the other side. The geometry over there is a little unruly. :)