This probably is gonna sound like captain obvious but I think Juliet is the reason Sawyer became head of security. She must have been feeding him intel on the others to make the D.I. think he was a very resourceful. The Richard conversation is enough to keep them on the island for a few weeks, but I'm sure Horace needed more convincing. He seems extremely paranoid. Probably from hanging out with Oldham at the prayer flag campground too much.