Warning: Contains SPOILERS for the season 1 finale of Watson.Watson just killed a major character, but it probably wasn't who you thought. Both Stephens' and Adam's lives were hanging in the balance during the first of the show's two-part finale, and due to Moriarty's blackmail, only one can be cured. After flipping a coin, Adam is given the vector, leaving the team to find an alternate way to save Stephens in season 1, episode 13. Considering that both characters are played by Peter Mark Kendall, it didn't seem far-fetched that the show may part with one of the twins.