Reading the blog after Mac's review got me thinking, we have seen the arrow before.

The arrow is this hole in the ground station, it looked abandoned and not completed. Now we know the purpose (and perhaps it was the second station created), to find out information about the "hostiles".

Why such a run down place, perhaps it was a secret place to drop off information and/or act as a safe house (I am assuming that the spy would join the hostiles.)

Also, do you think that the flaming arrows is the reason it is called "The Arrow" ?