I am not a physicist but with a very big passion for the subject. I might not be able to solve your equations but i love the mind games associated with BH. Having said that, let me move on to my observation: A kerr BH has two event horizons- The outer event horizon marks the boundary within which an observer cannot resist being dragged around the black hole with space-time. The inner event horizon marks the boundary from within which an observer cannot escape. Now the ergosphere existing between these event horizons is the main issue here. If I have a body inside the ergosphere (assuming that it is not crushed etc etc...), theoretically it should be possible to get out of the blackhole if it possesses the right amount of charge correct? Now again, if the body possesses the right quantity of charge would it not be possible to exist in a steady state (not moving relative to the event horizons). Also once the charge moves towards the outer event horizon, then it should lose charge. Suppose we are able to impart sufficient charge to this body, cant we have a situation in which the body will indefinitely oscillate in the event horizon? If I got my basics wrong, I am here to learn :-) ---Narcissus.