No one goes to work thinking: 'I want to kill someone today.' But sometimes people do get killed. But no cops want that.
When a cop shoots a person, that cops life gets turned upside down. You face losing everything: your job, your family, home, and freedom. That being said: 'Yes, sometimes there are bad shootings.' But what people have to remember is that when a cop shoots his gun it is done in a split second when the cop has to make a decision: do I live or die today.
I once was in a building in the Bronx trying to buy heroin from a young man, who decided to pull a gun on me and rob me instead. He got his gun before I could get mine. But in that split second the first thought that went through my mind was 'what will the job do to me if I shoot this kid'. A cop should never be thinking that in a life or death situation. That being said I fought him and he lost and was arrested.