 Shortly afterward, Robin returns, reiterating that she does not date co-workers, and she brought Sandy Rivers only to make Ted jealous, and Marshall tells her that Ted brought Mary to make Robin jealous.Marshall then (in an oddly telepathic manner) tells Lily that Mary is a prostitute, and Lily, who is asleep, wakes up and asks if Mary is indeed an escort.After a minute, Barney reveals that Mary is not really a prostitute, but a paralegal who lives in his building.