This is silly. A twitter storm is a pretty well defined, public event. Do you seriously think it would be common to post racist stuff on the internet, and then organise a permanent campaign against yourself, in order to become un-fireable for causes that are work related? A company that wants to fire you for your poor performance can do so, and if you sue them it's not going to be hard for them to prove they have a legitimate cause which has nothing to do with your self-organised mobbing campaigns.