If you did nothing BY CHOICE, then it WAS your will. Your argument is faulty in terms that in that case even if there was NO person tied to the alternate track, it's still cool not to flip the switch. The scenario, as encountered, has nothing to with you...until you choose to participate, right ? The moral dilemma stems from you WANTING to interfere and help people but being forced in a choice while doing that.

I can do better than that ! By what authority, cosmic gift or perspective did you choose chicken over beef, or brokkoli over carrots for your last meal, actively contributing to the overall death toll of that species ? You could have done nothing and no life would have ended !