Power for its own sake, and the cold brutal solitary serenity that accompanies such an exalted position, are precisely what the Rat/Capricorn lives for. If they think they've seen goals-oriented people in action before, they haven't seen anything until they've seen the Rat in you breeze past them on your way to the top, in such a way as to make Genghis Khan seem mild-mannered, of whatever hierarchy to which you see fit to belong.
This competitive streak can jeopardize the flip side of your success, which is the desire to be loved for your bad Capricorn self alone, and not because of position or possessions. Somewhere along the line the constant conflict between these two sides will have to be ironed out for you to be able to face life as an emotionally complete individual. Dangers to emotional equilibrium include tossing "inessentials" such as personal integrity, physical health, and even loved ones overboard for the sake of the next naked power grab. Beware the Ides of March!