When Johnny is forced to kill a childhood friend, Jessie Watts, in the course of arresting Jessie's brother, he's so haunted by the act he resigns.  This being Lawman not Law & Order, we know there won't be a cast change.  Johnny  changes his mind in the end when Troop's new deputy turns out to be a bombastic coward.  This was the last time Johnny turned in his badge and our favorite as it was the most realistically motivated.