The reason mach tornado ***** you (& every other IC player in the world) is partly because you're already committed to doing something like stupidly desyncing too close. The much BIGGER reason it ***** IC's is MK's will tornado higher then the pivot grab spacing, still hitting you. If you shield it, they retreat to a platform.
I've heard countless stories of people trying to figure out what to do. Usmash, Pivot-fsmash, di the first tornado hits outwards and grab.
Yeah this is a good way to pivot, but it's not really an answer to tornado.