Primarilly, when the guard looses sight of the player, he immediately heads back to his patrol which makes it hard to even keep the guards attention deliberately. I'm going to have to add something that makes him do a quick sweep of the area before heading back on patrol. So you enter his field of view, he starts heading to where he saw you, you leave his field of view, he stops, does a 360 to look for you, grunts, and heads back to his patrol.
He also tends to shake a lot when you are close to him. I know whats causing it - I just haven't put in anything to stop it from happening. Thats also on the todo list for tomorrow.