Warning: if you are easily upset from aggressive words and actions, run away, take refuge in your safe space and don't read this post.
Seriously, if seeing someone get shot or wounded upsets you, your time is better spent elsewhere.
In the wake of the deaths of Alton Sterling and Philando Castile, I present to you two videos, where lay (untrained) people (an activist and two reporters) go through what are known as "shoot/no-shoot" scenarios. When I had my CCW, I got the opportunity to train with systems like this. It is bone-chilling scary how quickly things can and will go south.
First video, a civil-rights activist and the reporter covering the story go through scenarios with people:
Second video, a reporter uses a system similar to what I used:
These videos should give you a better appreciation on what kind of situations police officers face every day. On how they have fractions of a second to decide who lives and who dies. Hesitation will kill the officer every time. The officer doesn't have the luxury to yell "DO OVER!" and try different methods. Once the perpetrator decides to take aggressive action, it's all instinct and reflexes.
And for those of you who didn't think the guy with a grilling skewer was a threat, the below picture is the kind of things that happen in a knife fight:
Just something to think about.