"I'm still not in the office at the moment but I will be there before 12 noon. You can go there first and wait for me for a bit. I'll have Xinyi pick you from the parking area." if she leave now, it is possible that she can arrive earlier.
Wang Xinyi might not know the connection between the two of them but she already saw him a few times before. Furthermore, she trusts Wang Xinyi so it is alright for her to pick him up and since time is of the essence, they don't have any other choice but to meet in her office since that is by far the safest location they could exchange confidential information wth each other.
This is not the first time that she asked Aaron to investigate someone or something for her so she knew that he wants to meet personally to relay the results of the investigation because exposing its contents would be very risky and Xi Ana knows that much.
