I dunno about reports, I avoid them like the plague, but experience tells me coppers are a strange body of men (and women), but armed coppers are stranger than most.
Police forces are known for their self-forming cliques and teams, so I can well imagine the Met firearms mob see themselves as superior to the woodentops and behave in a way of which most rank and file coppers wouldn't approve.
Worth bearing in mind that firearms jobs are reasonably common, but discharging a lethal weapon is very rare.
This means that nearly every copper who shoots someone will have never shot anyone before, even though they have years of firearms experience and lots and lots of training.
The last police shooting inquest I covered involved three armed response vehicles, so six armed coppers.
All had 10 years or more in firearms, but none had ever shot anyone using lethal ammunition.
In this case they tried to disable the suspect with a ballistic round, sometimes called a rubber bullet.
He went down after the first one, but got up again, so they hit him with another, but again he got up - in an even worse temper as you may imagine.
What did it is he levelled his pistol at one of the cops.
This brought forward two rounds from a carbine.
No one gets up from that.
Some speculation this was a 'suicide by cop', in other words the person knew if he pointed a realistic weapon at a polis or a member of the public, the police will pull the lethal trigger.