Serena's eyes grow wide and she nods.  Her coyness lost with the idea of losing her tongue.  She swallows hard and then brings a smile back to her face.  Use to serving and smiling when a smile is the last desire in the world, she manages to keep her face looking natural and unnerved.  The hand that her Lady squeezed would betray her as she squeezed back a bit too tight.  "I understand, Sir."  Her words were easy and soft, she even lowers her eyes as a show of obedience.  "My tongue shall be lost to me should it wag loosely."  She plays with his words a little as a show of courage and ease that was not in her heart.  She isn't sure how, but she managed to keep her limbs steady - no sign of shaking at atll.  She can only attribute that to years spent serving her Lady.  At the last minute she forces a memory into her mind that brings forth an impish nature to her face.  She lets the unknown 'gentleman' view this.  She thinks that if he takes an interest in her, perhaps he will be distracted enough from her Lady to allow escape - and she might keep her tongue.