Not blaming the 911 operator... but they could alert units and have them on the way, and keep the caller on the line. And maybe, maybe just ask, "Did you see a gun? Did you hear shots?" It was a freekin' toy truck for Chrissakes in the hands of an autistic person with the mind of a 10 year old.
Then maybe the 911 operator could give a more informed update to the officers responding. Same thing in the Tamir Rice case... the officer literally got out of his car and executed this poor kid in a matter of a few seconds.