i'm fairly new to the game but I'm wondering one of the abilities of my monk does like 40 mil damage, how would that work in pvp. wouldn't it always pretty much be an instant kill?
Players have mitigation through resists, armor, melee, ranged, and elite reduction. In addition, players get an additional 30-35% (depending on class) damage reduction for PVP. Some attacks can't be blocked, dodged and bypass some mitigation but at this point you can stack enough toughness to not get 1-shot.
my full tank doc self buffs to over 1/4 billion toughness. not to mention every class has cooldown skills that mitigate most/or all incoming dmg for a period of time and simply moving your character and learning how the different objects in the arena obstruct different attacks all combine to insure that no one shots happen if you know what you are doing.