It was made clear that Katharine and Jack had a long-term relationship before Tess came on the scene, and yet Jack failed to recognize Katharine's office when he went to visit Tess when she was putting on her act as a broker. Katharine has only just moved to New York from Boston. This is evidenced by what the recruiter says to Tess: 'transferring down from Boston, name of Parker,' as well as the fact that Katharine does not yet have a place to live (she tells Tess on the phone from the hospital that she's staying at her parents' house and her voice on the Dictaphone makes reference to her looking for a place of her own), and says to Tess of her and Jack: 'We're living in the same city now' which implies this is a new development. It is therefore perfectly possible that, while Jack knows where Katharine works and knows that it is at the same place as Tess (and assumes that Katharine is Tess's colleague), he has never seen her office.
