OMG. That would be my biggest fear ever! (Not that you could ever get me to go on TOT.) Could that even happen? There has to be some sorta safety over ride to get people down in case of power outage or something, right?!?
of course there are safety systems in place to get you off the ride if the power goes out .. at any point in the ride... I haven't experienced this first hand, however, I have absolutely NO DOUBT that Disney has contingency plans for EVERY RIDE, at every POINT.. to remove guests, should it come to that.
They are not amateurs in this game. They've done this a time or two. Any major organization has significant "risk mitigation departments" who's sole purpose is planning for the "unexpected".
You have no need to worry