Teenage risque' expose', explain or run like hell?

You are 13 with your 12 yr old G/F in her house in the den watching a movie with the lights out. Her parents are entertaining guess so you figure you would hear them come down the hall if they came your way, but in through the side door come dad. As he flicks on the light se says “Excuse me kids I need to gra……..”, he stops dead in his tracks with eyes as big as silver dollars a slack jaw and that look that says “Am I seeing what I am seeing?”. She has her top rolled up over her boobs, her left leg draped over your right thigh, you have your hands down her Daisy Dukes, and she has hers’ down the front of your Levis. You are both as shocked as her father is. Is there anything you could say to keep her father from tearing you a new one? Or do you just bolt and run like the devil was after you? {:-?