Her silence was a shelter against his sword-like sharp words. He wanted to pierce through her, get into her blood, make her bleed and suffer. These thoughts ached his heart. Instead, he pierced through his very self and made himself hurt unbearably.
Against all the words he muttered, she took her guard, i.e. her silence, against him. Silence enveloped her like a cocoon and protected her against mortal blow of words by him.
In this battle of hearts, nobody won.
They both lost.
They both hurt. They were both hurt.