There is certain look that turns PD on. Call this shock, surprise or terror. Part of it is wide eyes, however that is not all. some of it is dilated pupils, however that is not quite everything either. combination of arched eyebrows & gaping mouth, maybe? Whatever it is that defines fear best, it is everything he is looking for from babe. Her screams match her expression perfectly. They provide melody while his whip plays beat. Her pleadings are lyrics & her suffering song.