The Obie-Bunting showdown was only a screen for Archie's real purpose- searching for the traitor. He suspected that the traitor was a member of The Vigils. More than suspected. Few kids outside The Vigils knew that the day off from school was to have coincided with the Bishop's visit. And the letter to Leon had focused on the visit. Thus, the meeting was a place to begin his pursuit of the traitor, and instinct- instinct that had never failed him- dictated that he would find his betrayer there.