Never been to this particular base, but other bases I’ve been to have had turn-arounds just before you get to the gates/guards. I have trouble believing that someone who just made a wrong turn would keep on going. Even if this base did not have a turn-around, someone who just made a wrong turn would let the gate guards know that they were only turning around.
This was a probe.
Just looked on Goog Earth and it looks like a full set of pop-ups, to block north and south bound traffic. Probably about 400 ‘ past the guard house.