I suppose one hypothetical method would be to bribe or blackmail one of their officials to allow unrestricted access. Another could be satellite or low frequency long range wifi and a yagi to a relay. There are also many circuits that entirely bypass the GFW owned by companies even more strict than their governing bodies. Or maybe run some dark fiber in a tiny tunnel from China to India. This probably would not last long, but you could use a non visible laser to traverse the physical border.