In the "Central Circle" as denoted by the map, look at the outjutting pyramid-like reactors jutting out from the wall, preventing you from walking the full way around the room. Focus on where the little handrail meets the reactor. Facing backwards, jump onto that point, then facing away from the reactor, walk backwards and to the side to keep on that little ledge, around the reactor. This allows you to not have to cross the bridge while trying to get around. However, this leaves you EXTREMELY exposed, so 99 times out of 100, the is AI going to shoot you instantly. Human players have less of an accuracy, yet you still are exposed completely.