Saw the video. You really only need to watch the last 6-7 minutes to see the body cam vid in order to assess the officer's actions.
Looks like a bad shoot to me.
1. Assailant was armed with only the lock.
2. No guns or knives were reported in the 911 call meaning the officers had no expectation of a firearm.
3. The victim of the assault was about 10 feet away from the attacker and near the cops. She was already secure.
4. This was a very public place meaning extra caution must be exercised in discharging a firearm.
5. Seems likely that non-lethal methods could have been used to subdue the assailant. Had the shooting officer just waited a few seconds, the other cops would likely have approached him from the other side, pointing their guns. With nowhere to go, the assailant could well have just surrendered then.
6. No verbal warnings were issued to the assailant prior to the shooting.
7. Prior to the shooting, the other officers can be heard telling the lead cop to slow down and hold up.
I think it's manslaughter, and not only as to the bystander, but possibly as to the assailant. The assailant was not an immediate threat, was crawling away, not advancing, and was given no opportunity to surrender.
Edit: I was in error on point #4. A 9/11 caller did say he had a gun and had fired it. This still does not alter my analysis substantially because the assailant was in plane view to the officer and showed no gun.