Rose stops walking as the Doctor drops her hand and runs over to the TARDIS. She feels the psychic uncertainty coming from their baby too but doesn't understand it completely until she sees him.
Looking across the Plass as he runs towards their baby she sees past Jack and recognizes the flapping brown of a very familiar coat. It's him the 'Other Doctor' the one in brown, the one that left her! The psychic uncertainty makes sense now but nothing else does. Her mind goes numb and she shuts down all she can do is just stare at everyone and everything going on in the Plass.
As the two Doctor's stand in front of each other glaring back and forth she recognizes the other Doctor's veiled mention of her and it snaps her back to reality.
She had always assumed they would run into him again sometime but never did she expect it to be so soon; and most certainly not like this. She rubs the ring on her left ring finger and slowly she starts walking over to Jack her eyes never leaving the two men as they argue.
She stands next to Jack for a bit while the two men she loves argue back and forth. Finally growing tired of the whole 'Time Lord-y' argument and sensing Jack's growing frustration, she steps in between the two Doctor's. Her back to her fiancee, face to face with the man who left her. She glances at him, suddenly feeling very shy, "Ello, Doctor! Nice to see you again. Look at me, all brilliant, came back again."