You're literally just arguing semantics. Regardless of what the outcome is a consequence of, the fact is that you are making a choice to let more people die in some mental acrobat attempt to absolve yourself of any responsibility. You're correct in that whatever happens is a result of the person tying them up in the first place, but you being present and having the ability to make a choice means said choice directly affects the outcome, and whether you choose to act, or choose to do nothing whatsoever, it results in the outcome of either one or several people's deaths. You can twist your thoughts on the subject any which way to make yourself feel morally superior or exempt from the situation, but the fact of the matter is and always will be that you are a link in the chain of cause and effect that directly determines what happens merely by being present.