There's a very small difference between the range at which you can see Titans and Titans can see you, and they can't see quite as far as you can. So what you do is first, save your position. Then edge v-e-r-y v-e-r-y s-l-o-w-l-y towards the Titans, holding down the "A" key to fire a continual stream of arrows (this trick works beautifully with a bow of Carnage). As soon as the arrows start to hit, stop where you are and hold the "A" key down. It'll take some time, but they'll just scurry around where they are, looking for the source of the arrows, until they drop. Don't be tempted to go nearer, though. Once they see you, they'll come after you, and then all bets are off.