So from my point of view, that person would not do anything, therefore, he/she would not be guilty of not killing anyone?

I think if I know that 5 people are going to die unless I change the track of the train to kill one person, then yes, I am still "guilty" of not saving those 5. I have no responsibility for whatever happens ONLY if I know nothing about it. Once I know that a certain action will cause a specific outcome, I do get some part of responsibility for what happens.

As for the question and the choice... It will probably sound immoral, but at this point I would chose 1 person that is dear and important to me over 5 strangers (unless that person asks me not to do it or I know for sure they wouldn't want me to do it). Which is another dilemma in itself.

I also think none of it is about guilt. It's not a matter of morality and "good or bad". One human life cannot be out-measured by 5 human lives, and we cannot put a price on human life in comparisons of amounts.

There are lots of people on earth. Lots of people die every day, and no one goes on mourning for them non-stop. Strangers, people who are not personally acquainted, don't go crying over those thousands of people who die every minute.

It's only when a large number of people dies at once that we suddenly feel shocked or sad. And, supposedly, we feel "sorry" for the dead. But I think it's not sorrow or great compassion that drives people to notice catastrophes that take away lives of many. I think it's mostly fear of death itself. Death becomes more noticeable that way.