Ying Ying agreed and they quickly went to a big teahouse where Yao Ling had been waiting for them. She had chosen a private room so that no one would be able to see their meeting here and they could talk more freely this way. Ning Jie had specifically changed Ying Ying's clothes before they came here so no one would recognize her.
She didn't want Yao Ling's reputation to be ruined just because they thought she was helping Ying Ying for real! Ning Jie also sent a person to notify Yao Ying what had happened on the street just now. The person that she sent was the one who had gotten the job to spy on Ying Ying so he would tell everything clearly to Yao Ying.
Ning Jie wanted to let him know that he might be a traitor or something like that in his past life! He needed to prepare himself --- of course, they didn't know whether that claim was really true or not. However, it was the only clue that they had for now. They needed to treat it seriously.