Let's say that you have totally free will, and I also have totally free will. That means that there you are FREE FROM my will. It literally means I CANNOT do anything to you. There you are, fully causal, fully choosing, and whatever you will happens, and whatever you don't will doesn't happen. So there is no room or scenario in which I can "cause you", in any way. Since we are equal children of God, and God is our only mutual cause, neither of us EVER has the ability to do anything to one another. The only thing that can be shared between us is love.
With this in mind, as the secret of salvation says, if anything is happening to you, YOU must be willing it. You must be doing it to yourself. Which means it is literally impossible for anyone anywhere to do anything to you in any scenario. It also hints at your immortality because obviously if nothing can happen that you personally do not will, if you stop attacking yourself you regain invulnerability.
So by the simple fact that you are TOTALLY FREE, as in, like, independent, a whole being who can choose for themselves, whatever they want, that being true means I cannot will anything against your will. Jesus also says this, that he cannot overthrow your will because your will is as powerful as his. This is why he cannot "take away" from you stuff that you aren't willing to let go of, and it's also why YOU have to be at least a "little willing" in order to move towards God. And also why no-one comes to the atonement except through full willingness to do so, because "God does not coerce".
Not even God overthrows your will, or goes against it, or forces you, or requires you. So that simply means that because your will is TOTALLY free from all other will, and you can choose the direction of your mind's creation, and because there is nothing to OPPOSE your will, whatever you choose is what you will receive, and what you don't choose you will not receive. This is the secret of salvation - the acknowledgement of YOUR freedom and the freedom of all your brothers. "Heaven is a choice I must make."
It's also why your self is ruler of the universe:
"It is impossible that anything should come to me unbidden by myself. Even in this world, it is I who rule my destiny. What happens is what I desire. What does not occur is what I do not want to happen. This must I accept. "
It's also why nothing can happen to you other than what YOU will against yourself:
"It is your thoughts alone that cause you pain. Nothing external to your mind can hurt or injure you in any way. There is no cause beyond yourself that can reach down and bring oppression. No-one but yourself affects you. There is nothing in the world which has the power to make you ill or sad, or weak or frail. But it is you who have the power to dominate all things you see by merely recognizing what you are."
It's because you are free. Free to choose. Free to elect. Free to decide. And your decision has power. "The power of decision is my own." And nothing can oppose this power.