There is a whole lot more than than the number 9 in their report but if that is what you are hanging your hat on then okay as you evidently can't or...
In other words, you can't back up your statement that this man is an idiot nor are you able to dissect his investigation and tell us what you believe...
If the shooter can identify soemone trying to get a gun out then that would require him to focus on that particular threat and not the other students...