Sorry. But I hardly do arenas on engineering. You need at least a tank which was what I used to have run with me. Arenas are all about positing to LOS the ranged. Making the melee regret stepping into your AoE which you put on yourself. Standing back and waiting for rest to get into the fight before engaging is good. Honestly this is a class with no god DCDs. Unlike sorc or merc or jugg. It really comes down to strategy. Like for example when you know there are 2 enemy stealth’s. You might want to get into combat quick with the remaining 2 and pop entrench quick so the stealths can’t just phantom stride open on you or stun you. Then drop diversion on them to reduce their accuracy and use your burst on one of them