Many (most) police officers are poorly trained in use of their weapons. The pressure from a serious engagement causes vulnerability to panic, as opposed to reverting to training.
If you've ever been to a pistol range and seen a cop shoot, you'd know .... most of them aren't very good.
From the NY Post account:
"I heard eight or nine gunshots. I walk outside and I see a cop car go flying by," a Fair Lawn resident told The Post.
If the surviving cop got hit twice and the DOA cop four times, the inference would be that the LEO's only got off two or three rounds to the bad guys six. "Ear"witness accounts, however, are highly unreliable.
The cops today are not like the cops of yesteryear(who usually never needed more than 6 bullets). The cops today carry a gun only because it is part of the job, many of them never even owned or fired a gun before they became a cop, and are not pro-gun. Most cops today do not know how to shoot very well, and do not handle guns safely. Cops today rely on high capacity magazines and spray and pray, not worrying about where all their misses will go or what innocents behind the targets will get shot. I have seen many young police cadets come in to get their guns registered, and they didnt know the first thing about guns - and didnt seem to care either. Most of them barley qualify, and dont practice or shoot guns any more than they have to.
There are also some police departments who boycott NRA sanctioned shooting training events/courses - as a political policy against guns.
I have seen a big city police "pistol team" who could not shoot a 12 inch plate more than 2 out of 6 times at 10 yards.
No police deparment will choose a capable middle aged layed off IT worker who might have sound judgement and excellent abilities as a cop, instead of a young immature college student who doesnt know squat.