Unless I'm missing something, what happens, happens, and can't be un-happened. This becomes obvious pretty early on, and grows more significant as your life flies by. The happenings pile up. And in that pile there's lots of things you wish you could make un-happen, but that doesn't seem to be the way that things work in this dimension.
Now it's possible that our human perspective is so limited, partial, and even false that this business of happening and unhappening is just a great misunderstanding. I suppose we need to leave it to the astrophysicists and cosmologists, and philosophers and dime-store comics to sort things out.
So until we learn otherwise, there's "what happens." And that's all we get. What happens.