I think that there is no such thing as "right" perception. Since everyone sees events and ideas differently, we can only say that there can be right actions. I would define a right action as the action taken, based upon a person's perceptions, that causes the least harm on the whole. This can be anything. If a person believes so strongly in such-and-such that if such-and-such tells him/her to kill his best friend he would do it, this can be a right action if the person thinks that such-and-such is the ultimate authority and that the only option in a case such as this is obedience.  He/she may perceive that the ultimate harm is to harm such-and-such. I'm not endorsing this action, you understand, I am merely seeking to accurately definte "right action" based on my personal ideas. 

I will continue on to say that the best way to prevent someone from doing such a thing is NOT to prevent  them by physically intervening. This will cause them to think that you are immoral because you have caused ultimate harm by disobeying such-and-such. The correct way is to convince them (now I am departing the "such-and-such" example, because frankly I don't know how to dissuade someone who believes in something like that so strongly) by telling them of the lesser harm of some other action.

I am not definitive at ALL on this matter; this is only meant to get feedback  on an idea.