I imagine that the Old gal Hill knew the enemy had missles. She also would have known by then that she couldn’t trust anyone in Libya.
It would have been a greater nightmare to send in help and have them get picked off by weapons we supplied to Libya and were probably trying to get back.
We have no business having an ambassador in a country if we can’t trust anybody there, and if they wouldn’t let us fly over their air space to protect our own embassy. If these are the “friends” we spent our fire-power to install, then we’ve got a lot bigger problems than just an embassy attack.