This is probably 100% correct, imo.
You have to stay in your assigned area.
Had there been an emergency call in their own duty area, they would have been unable to respond.
You can’t just leave your assigned area like that.
HAd they been needed in the SWAT response to the school, they would have already been there.
Or, as heard in its more familiar form as the anthem of unionized gubermint workers: "not my job."
All they have to do is just jump in the cop car and turn on the ignition and lights and siren and drive...
There they are, ready to help, and in position to kill a murderer since no one else was...
Oh one other thing, they can also tell the boss when they get a chance to...