The police do need to be reformed. They're killing folks for no reason. Also there is no law that says a police officer can be charged with a crime for not risking their life to save someone else. Heck, I don’t know of a law that says the officer can be arrested for not saving his own life or another officers life.
Don't be a retard and think that they are infallible. The police need to be de-unionized, and better trained. They act more like fucking commandos than civil servants. They're highly paid and pensioned gang members in most cases. Use your fucking brains.