American police officers training depends on the state. It's generally a months long process and quite rigorous physically and mentally. I have a friend who literally just went through this and I can say he definitely had a lot of training. At the end of the day what they are trained to do is come home at the end of the night. Keeping themselves safe is top priority in a job that can put them in a lot of dangerous situations. We've had many discussions about this line between police officer shootings and justification.