There were many talents working under Madam Grace. With great money to throw around, there were many who were willing to throw their lives away for her. She could even get professors to swear loyalty to her, much less two underlings who were good with Chinese. Since they were expanding in China, other than knowing how to communicate herself, how could she not have a few underlings that knew Chinese?
Therefore, when Brother Shuang ordered his lunch and gave an excuse to make a call, without even an order from Madam Grace, the bodyguard who had been following them from a far moved to Brother Shuang's corner to eavesdrop on the man.