Whew. Lots to cover here.
When I was a cop you were allowed, under certain circumstances, to shoot at a fleeing felon. Chiefly, if you had probable cause to believe the person had committed a serious felony and that their successful escape would put the community at risk.
An unwritten corollary to this was "if you shoot at a fleeing suspect, you had BETTER be in the right, and you'd better be able to account for every round fired and no bystander injuries". Otherwise, it was your career for sure and maybe your arse.
The upshot was that not many fleeing felons were shot at, and those that were generally deserved it. Cops didn't want to take the risk of being found at-fault unless they were SURE the guy really had to be stopped.
Now, to address this fallacy about "stray bullets".
Anytime a cop shoots at someone there is a potential risk of "stray bullets". Hail, anytime anyone shoots at someone that risk exists. When it is a "two-way-range" and the perps are shooting back, quadruple it since most perps lack any concern about bystanders.
This is why part of your training underscores the risk of opening fire under conditions where bystanders may be put at risk, and the emphasis most good departments place on marksmanship and judgement.
A "fleeing felon" doesn't up the risk that much. Either you have a clear shot without bystanders in the line of fire, or you don't take the shot.
Granted cops are human and mistakes can be made; errors in judgement also. Granted there are a few jerks who abuse their authority, too.
The serial killer we had down here in my immediate AO brings this home to me in a way it might not do for others. If the cops believed they had located this guy and he tried to flee, they DAMN WELL BETTER HAVE SHOT AT HIM!! He was a KNOWN threat to the community who had murdered repeatedly!
We had cops standing in the middle of intersections with M4s and Remington870s, scanning the drivers of passing vehicles looking for the guy. You bet your assets they would have shot him if he'd tried to flee.
Life isn't safe. Sometimes you have to balance one risk vs another. Allowing for shooting at dangerous felons, under certain circumstances, is one such issue.