Because if you leave a backdoor for yourself, you've also left a backdoor for everyone else. See how tech companies operate today. *shrugs* I am happy with the level of explanation shown in Wheel of Time. I don't need everything explained and would go mad if an author tried to. Not only would it be a gigantic waste of words, but it goes against the grain of what makes a sensible world to me. There's always mysteries. I get that's not for everyone, but there we go. Plenty of books that like to tie everything into a bow.