i was swimming using a diver and was 300 meters from shore , the ai was stand still with his right side towards me (i was right at the edge of a 180 field of vision)
then he turned around (unscripted) and started firing at me

Tried another scenario:
walked toward a guard while i was in an area filled with bushes and trees , i was 200 meters away and again to his side , guard spots me almost instantly turns and starts firing at me