What about RPGs or repeated hits? What about if they cripple the Baghdad Airports? you can hide all you want in the most indestructible building, but if food water or oxygen get the better of you, then you are screwed .
It’s not about metaphysical impregnability, it’s about time for evac.
You wouldn’t believe some of the ordinance they can put on door and window mock-ups and it can still keep a jihadi working for an hour to bust in.