It's an regular item and once you use it, it's gone. So depending on your party setup and strategy, you might want to bring more than 1. My pt had 4 last night and we used 2 of them (2nd one was kind of used by accident).

He doesn't run very far, more just a randomly around your party a bit. You dont have to chase him and if you have nukers, it's a good time to land some nukes in.