Guild Wars 2

I seek a pistol/pistol build for PvP.
My idea is to pick out a target, get him down and vanish.
I often saw thieves who were unfinishable, they used stealth 3 times in succession.
How do they do that, what build do they use?

Go p/p full zerker 5/6/0/0/3. As heal pick Hide in Shadows (1. Stealthoption)
Utilities are Shadow Refuge (2. Stealthoption) Blackpowder (3. Stealthoption) and roll for Initiative. Strength runes for might and damage. For sigills, dunno how it is called, but it gives you 1 might every time you crit with 1 sec ICD.