Good post !!! I've read all the posts here, and elsewhere. It's good to see the peanut gallery is alive and well. Unless you have faced a drug crazed individual with a knife, you have no business second guessing the officer. I can say that the first thing that happens, is your arse slams shut. The next is, your training automatically kicks in. Only he knows what was going through his mind.
Its typical that everyone can disect over the course of months, what the officer did and why. He had the matter of seconds to make a decision. He didn't have the luxury of videos, witness statements, pathology reports etc etc....
Did he overreact, not likely in the first instance. Was he justified in shooting again once Yatim was down, maybe... if in his mind, Yatim was getting up. He had no way of knowing how many rounds hit, or their effectiveness. That info only came from the PM.
A lot has been posted that Yatim didn't rush out of the car, some by a couple of posters who should know better. In edged weapon confrontation, critical distance is important. The officer was well within critical distance. Had Yatim rushed out at the officer, he could have very well killed or critically injured the officer, even after being shot. This concept forms part of their training. It's not like the movies......people don't fly backwards and drop once shot.
This is far from over. There will be an appeal......