Dexter encounters this Docent when he's in search of a man that he saw at a previous crime scene and creates a story to talk to her. He says that he accidentally poked a hole through a painting of his boss's with his elbow, but before he can really finish the Docent leads him to a room (with somewhat of a "snotty attitude") that is playing an informational film about art restoration. Dexter feels this won't help him but she asks if he's seen the film before, which he says he hasn't...so she instructs him to go ahead and watch it. Dexter reluctantly sits down but finds the film actually informative: it turns out the man does work here, as he's right on the film.
Dexter stands up to ask the Docent who the man is and she simply tells him to shh, which causes Dexter to just head out the exit while thinking the thoughts "Worst... Docent... Ever". She watches him leave, likely because he's leaving during the middle of this "informative film" and this is the last she is seen.