The “experiment” Rowan’s telling Laurel about is whatever Brian and Melody Crawford were talking about when they left Brian’s office. The reason Rowan’s concerned about it (beyond all the ways one of Brian’s extracurricular activities could blow up in the firm’s face) is that Melody took an interest in having Lori as an assistant. Because Rowan is already on thin ice with Lori’s father, she’d rather that she doesn’t get too mixed up in the latest impulse of Brian and Brian’s colleagues.