I’ve been in enough “Bunker Dives” to tell you that no one leaves shelter just because there hasn’t been incoming for a few minutes. Once you are in there, you wait for the all clear to be given (or other instructions) before you exit.
With the surveillance systems that the US has, the command personnel have a real good idea if there will be any more incoming, whether it is rockets or mortars.
True, but, that sort of timing and targeting* is still a typical terrorist attack.
*Within certain limits - the rockets used are not terribly accurate. One can reasonably say the attackers were not trying to hit the far end of the runway, but whether they actually targeted bunkers vs. barracks, we don’t know.
IMO, the Mullahs actually wanted large US casualties, and believe, incorrectly, that would be a proportional response that would also cause sufficient political pressure to “dump Trump” (ie., most Americans are sissies) whilst they endure our following retaliation. I doubt they care how many of their own people are harmed - they sent children by the thousands into mine fields to clear them - by getting blown up - in the Iran / Iraq War.
It’s also important to consider that the Iranians are not a monolith, and not even two 100% divergent sides internally. They have various power struggles galore. Do we REALLY know who the advance warning originally came from?