Really? I'm not being crass, but it's really easy to say that in such certainty without thinking of the wider possibilities, options or consequences.Sorry but anyone that shoots someone in the back 7 times is not using any sort of dynamic risk assessment.
Purely hypothetical: if you went into a room and an adult was on top of a child, with their back to you, with a knife actively trying to stab them to kill them.
You're stood over ten yards away and are armed: do you run over and try to detain? Do you reach for a baton, CS spray or Taser? Or do you shoot in them the back?
Sorry, I know what I'd do until they were no longer a threat and I say that unashamedly. Obviously, the events of the other day are a totally different scenario...
... but in that situation the use of lethal force would not just be justified, but arguably a necessity. It's a big step to take someone's life, but sometimes it's needed.