He was probably AFK, you were hitting him for 1.16k with Rapid Shot. I assume he has atleast 50k HP and everyone in Etain carries Cure Potions (poison dispel) because a lot of people have Toxin Weapons.
Even if he wasn't AFK, you probably weren't the only person hitting him so I feel sorry for the people you KS'ed for the kill on him because that's sad on their part not Besa's
It's PvP people are supposed to die! What's the fixation with SS'ing kills