The possibility is him,what they had and now she may not have it back. He has taken everything with him, her heart, her feeling. He's stopped her heart from beating by taking it with him. She has nothing left,nothing else to do, now that her love has gone. She's falling from the pain she is going through of the separation. She's asking if he can hear her silence, her heart stopping, he's the only one that know's because he has her heart so she wouldn't know if there is a silence. When he leaves she knows that he's a thief by taking her heart with him. She's asking when it's all going to be over, and the reason why she's so shut down. He's the only person with all the answers. So all she can do is wait in the silence of her sorrow.