Ambassador Stevens was a CIA spy......so were the two Seals who came to his aid.
The “consulate” was a safe-house and intelligence center for CIA ops in Benghazi.
The real scandal is how did Al Qaeda figure all this out, including Stevens travel schedule, to plan the hit?
In my experience, the foreign nationals who staff embassies are involved in most embassy in-country travel. He could, however, have traveled via surface in a non-official vehicle unbeknownst to the locals. In any event, you can be sure that the locals tipped off the bad guys.