Far Cry 4 comes out next week and Gamespot has an article on how it can be beaten in about 15-20 minutes.
The short non-spoiler version- early in the game you're given a choice of options which are basically "Start the game" and "Do nothing." If you take the "do nothing" route, the game will indeed end uneventfully. In movie terms, it's like Breakfast Club if all the students just sat quietly.