It looks like your questions have been sufficiently answered, but I'd like to share this story with you. This happened to me recently:
At about 01:30 in the morning, I pulled up in my cruiser to a medical office building to follow up on a theft case I was working on. The parking lot is not very well lit. As I step out of my cruiser, a man runs towards me, holding something in his right hand. It's dark, and all I can make out is that it's thin, about 6" long, and one half is wrapped in cloth. He starts swinging it around, yelling "I'll ******* kill you! I'll eat you! I'll **** you!"
I draw my firearm, point it at him, and start giving loud verbal commands. At the same time, I radio dispatch for help. He's not responding to my commands. He's still yelling, swinging the item, making stabbing motions, making threats. He starts approaching slowly, I back off to keep distance. We start moving into the street. About that time my backup shows up. Other officers draw down on the man, start giving verbal commands. He's still not responding.
At this point, it would have been prudent to tase him, but my department doesn't equip us with tasers.
We finally end up in a well lit area across from a restaurant (and boy oh boy, were the cell phones out.) As we're continuing to go back and forth with this guy, one of my backup units gets in close enough to see that what he's holding isn't a knife, and doesn't look like a shank, either. He hits the guy with OC spray to no effect, and then moves in with a baton, striking the hand holding the object. The guy finally drops the object, we all move in and take him down. Bonus: He's covered in feces and urine.
So what was the object? All that time? A ninja turtles toothbrush.
Here's the thing: At any time during that encounter, from the time he initially approached me aggressively to the time we were finally able to see what the item was, had he charged at me or another officer, or a bystander, I (we) would have shot and killed him. Now I did have the presence of mind during the encounter to wonder if the item was in fact a knife, because I've had similar experiences before. But given his behavior, and the way he was brandishing it, I had perfectly good reason to believe that it was a weapon. More importantly, I'm not going to let my own doubts get me killed.
So what if I had killed him?
Well, the cell phone videos would be out. The media would report, initially, the most simple version of the story:
Townsville Metro Police Kill Man Wielding Toothbrush.
Reddit is pretty quick with things like this, so shortly thereafter on the front page:
Police officer MURDERS man over ninja turtles toothbrush.
The initial news headline would play out for a bit, until they got a few more details.
Townsville Metro Police Shoot Young Black Man Wielding Toothbrush.
Another media outlet, upset that they didn't get the initial scoop, goes with something a bit more sensational to grab the media consumer's attention:
Townsville Police Kill Unarmed Young Black Man.
There you have it. The average media consumer's opinion has already been formed by the headline - many won't even bother to read the story. Even if they did, the story will contain the most basic of details. Cops shoot guy, guy only has toothbrush.
Here's what the stories won't contain: My thoughts and feelings upon the initial encounter. The things that I can (or can't) see. My fear. My wondering if I'm about to kill a man, and how I'm going to deal with that. Am I going to break down like so many others? Become an alcoholic? What if it doesn't stop him? What if he kills me? I need help. Where are they? What's taking them so long? Who is this man? Why does he want to kill me? What if a bystander walks into this? I can't let him take a hostage. Goddamnit where is my backup?!
And then later: My god, I almost killed a man over a toothbrush. Would it have been justified? Maybe the courts would have exonerated me, but would I still get fired? Could I forgive myself? Great, I've got someone else's **** and piss all over me for the third time this week.
And then, much later...well, just imagine, after all that, how it feels to see someone watch a massively abbreviated news report on the incident, form an entire opinion based upon that miniscule amount of information (and their complete lack of qualified expertise or experience) and condemn me for my decisions. As weird as it sounds, this is my job - my expertise. Criticizing me for how I deal with a **** covered maniac is no different than you walking in on an open heart surgery and telling the surgeon he's using the wrong scalpel.
Don't let the media form your opinions. Understand that investigations can take a very long time. Most importantly, understand that these situations are often so massively complicated that no journalist could ever truly convey all of the details - especially what's going on in my head when I have to make that critical, life altering decision.