Pretend you are dying and you want to stave off “The Grim Reaper.” If you deliberately smash a mirror, doesn’t that ensure that you will be around another seven years, to have all of that bad luck?
I think that I understand what you’re saying, if so then I’m guessing you could say that you dying would part of the bad luck, and then for the next 7 years bad luck things would happen to your grave. Say if you didn’t break the mirror then some crazy new treatment might be approved at the last minute and it saved your life and many others.