This was one of the most frustrating scenes. The gall and nerve of the emperor to slap Ruyi. It was indeed the Empress Dowager who meant for Xiangjian to drink that tonic (which makes a woman sterile) but before that, during the audience with the Empress, she herself brought up the matter to Ruyi, that she didn't want to have a child with the Emperor. She did not love him, and she did not want to bring a child into this world with him. Since she was forced to stay in the palace, she wanted to be in control of the rest of her life as much as possible. The emperor selfishly blamed Ruyi because he couldn't face his inhumanity.