This thread has deteriorated into an armchair dissection of a tragic event LONG afterwards and with alleged facts not known at the time.
The officer responded to a report of a person waving a gun. (Note: not a noise complaint, not a missing bicycle - a person making threatening moves with a gun.)
He arrives and finds a man who ignores the officer's commands and lifts his shirt, revealing a gun butt.
That is ALL he knows at that instant.
Everything else - the man's age, whether the gun is real or not, whether a BB gun is a gun or not, what the original caller said, what the dispatcher didn't say, or why the man has ignored the officer's commands - cannot be known at that instant. And that instant is all the time the officer may have.
