I think there's more to this story that will come out .
This business of training cops to instantly shoot when they hear the word 'gun' is a very dangerous practice !!!
There was a recent example of this when a situation involved two different agencies. A member of Agency A arrived ,in plain clothes, carrying a long gun.The members of Agency A knew him so he was no threat to them. Members of Agency B did not know him and one of them shouted 'gun' and the officer was shot !!!
Poor training , stupidity etc !
And Watson , bring your revolver !