Merc's and their Mirror AC

I was in a WZ last night and I watched this merc just spam his tracer missle (if thats the right name for it) over and over. Granted he was 45ish, but he was just mowing down people with it and even when I jumped on him as a 30 assassin he just spammed it till I died.

Now I am sure I noobed it up. I interupted him then stunned him all trying to break the damge out put of that missle but it didnt seem to help. I just watched him do this all WZ long.

So 2 questions is that class that easy mode? Also, How can I improve my play as a tanksin or Decption(sp) based sin to beat him? I dont have the AOE from maddness which no doubt would have helpped and so would have my level being higher.

Do I need to shrug this off as a level difference?

At 50 merc/commando spaming those at 4k a ht lol