As Jin was messing around to complete his dungeon instance, the Grey Bears Squad finally got to the Great Wall of China from the coordinates based on Jin's World. The System does not have any surveillance prepared nor has it used its powers to scout the place in advance. Thus, the area that the Grey Bears had teleported to, was a destination which everyone had no idea what was installed for them.
"We should have asked for a plane… or a helicopter," Yinn said as the teleportation had brought them several thousand metres up above the sky mainly because the System did not want any disruption of the portal. What if the coordinates of the portal had been stuck in between buildings? Or is it in some pillar? It would be a waste of portal energy and the System's resources.