Rivalarrival

Gonna go with simpleton, final answer.

who's chasing you with a clearly non lethal weapon is

The weapon in question is a metal blade on a stick.

It is readily capable of destroying an eye. (Aka: "Grievous bodily harm") It is readily capable of severing the carotid artery. (Aka: "death") It is capable of causing a wide variety of similar permanently debilitating, disfiguring, or lethal injuries to the officer in a very short period of time.

The video shows that the kid was attempting to strike a retreating officer in the head or upper body. Any person in the officer's position would reasonably fear a significant possibility of death or grievous bodily harm from this attack.

I therefore reject your assertion that the weapon being employed against the officer can be reasonably described as "clearly non lethal".

But I'm still here scratching my head with the rest of the neighbourhood that hasn't been affected by this mysterious river.

That's pretty much what I'm getting at: you don't even know the river exists, let alone the fact that there are people living near it. You just assume that the US is living in a mountaintop commune, because you and everyone you actually know lives in one.

We aren't.

The only nation in the Americas that actually qualifies for your little club is Canada. The rest of North, Central, and South America is living in a dank river valley.

How should police have handled it?

The bodycam video shows the officer approaching with his gun holstered, drawing it while backing up, turning and trying to run away, while the kid quickly closes the distance and tries to strike the officer's face, head, and upper body with a long-handled tool.

How should the officer have handled this?

How would you have handled this?

If a random person were attacked in such a manner, is it possible that they could have lost an eye? Is it possible that they could have been permanently disfigured? Had their carotid artery severed and quickly bled out? Been knocked out?

Is it possible that a reasonable person could have reasonably believed this attacker posed a credible, criminal, imminent, threat of death or grievous bodily harm to an innocent person?

From the body cam videos you can easily glean the size and shape of the tool in question and how the kid was handling it, but the clarity isn't enough to conclusively determine the specific tool.

Bodycam video

Officer was backing away from the kid, and turned to run away from him. The officer was actively retreating from the attack at the time the shots were fired.

Two officers were present. It is not clear from the video who fired the shots. It is very clear, however, that the kid was actively attacking the officer.