Olivia has calmed down by the time they reach the scene of the crime. Peter distracts the annoyed and annoying restaurant owner who is ticked off that all his customers rushed out without paying their checks yesterday. You know, after the murder. Peter gets mouthy with the guy and they piss each other off until Olivia proves that she has more cojones than either one of them. She found a piece of a broken cup on the floor of the restaurant and thinks that it is a clue. So following FBI protocol she instantly grabs the douchebag restaurant owner by the lapels and throws him against a booth, demanding to know who was sitting at that table. The owner says it was a blonde guy with a scar. Olivia knows who that is. She releases the douchebag, and marches out for justice leaving Peter and the guy staring in her wake. Peter catches up with her outside and asks to know what is going on. Olivia knows the blonde guy. She has seen him before.
She and Peter must have made the trip back to Boston in silence, because Olivia doesn't tell him how she knows the blonde guy until she points him out on the subway surveillance tape back at the lab. Bet that was a fun car ride. Astrid zooms in on the man's face. He is blonde and has a scar. Walter is intrigued...with the coffee. Peter moves to snatch it out of his hand, but Walter manages to focus and drink coffee simultaneously. See? He is a genius. So with the pictures of Scarface at the subway and a witness placing him at the restaurant (or at least some other blonde guy with a scar), they have a man who was at both crime scenes. He's the link. He was at the table where Olivia dreamt she was sitting and at the platform where she dreamt she was standing. But she never saw him. So obviously she was him. Duh. Dreams aren't always literal, Walter explains, so she must have been dreaming about Scarface. Olivia is much relieved that he was actually the one murdering people, not her. But there is still that hanging question about why she was dreaming with him. I don't know about you, but I totally have "Dream a Little Dream of Me" stuck in my head.