If you're not familar with the noise that modern Jet Fighters produce, then you'd probably call 911 wondering what was going on too, or if they didn't see the fighter they might think than another airliner was "going down".
There used to be an annual air show at a smallish airport near my parents house and when the first jets would arrive 911 would receive several calls from people that didn't know what was happening.
I remember one year when a B52 flew directly over the house at low (I mean low) altitude. After it was gone we went out to check for skid marks on the roof, and to see if any shingles were missing. It shook everything.
Looking back, the experience was pretty cool...I can picture us looking up from the dinner table and stareing at the nose of the plane as it approached the house, then being extremely surprised at how loud it was.
It's a good thing that new jets can fly faster than sound....because if they didn't, they couldn't sneak up on anything.
As to why someone would run their plane into a building, I have no idea.
- TK