Rift Quest:Field Tested, Goblin Approved  

Applying the poison is ranged and has a long cast time, and is easily interruptible, so it must be done before engagement. It appears to have absolutely no effect on them except to make them very angry... not much of a change, really. On the bright side, the quest updates when you spray them, not when you kill them so if you have any root/snare/stun ability you could just spray and run! Or, stay and pick their pockets after!