Yes of course we have to worry about friendly fire. Undercover cops and other good guys have in fact been mistakenly shot or killed by LEOs. It is a real life concern.
And it's just one of the factors that make dealing with an active shooter a problematic activity.
So leave the gun at home, bring camera, pen and notebook and bullet proof underwear.
Good intentions will always be pleaded for any assumption of power. The Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern will, but they mean to govern. They promise to be good masters, but they mean to be masters.