Useitem, then kill mob not attacking me?

[Ruinit 11]

How do you use an item, wait for story and then attack and kill the mob when they do not attack you? It's for this quest http://www.wowhead.com/quest=26674/mistmantles-revenge 

and I have 2 objectives 1 to use the item at a hotspot, 2 to kill the mob that spawns after the story. Uses item fine but keeps using item on cooldown and will never attack mob?

Thanks

[Ruinit 11]

bump

I even put this in before pulse runcode for attack before attacked and it still won't move to the killloot part

http://www.wowhead.com/npc=315/stalvan-mistmantle he is an npc if that matters?

from log 

[D] 21:50:30 - [Fight] Mob seem bugged
21:50:30 - [Fight] Can't reach Stalvan Mistmantle, blacklisting it.