This episode marks two pivotal moments in Ms. Watson's life: her first ever being arrested and her making her career pick. She chooses for the world that had been opened up to her the day she met Sherlock. She embraces her internal detective and adjusts her occupation on her profile page. OK, she made some mistakes in her first ever investigation, buy hey, who cares, the woman with the crazy story helped to solve both cases!
Also we got a peek into her social life when we were introduced to her friends, who genuinely seem to be worried about her. However, Ms. Watson seems to walk a way that might potentially lead her to alienation from her friends and turn into a solitary Holmes-like figure.
On the whole, quite solid acting from Ms. Liu's side - she seemed to enjoy every minute of it - but the bad guy was kind of flat and uninteresting.