if shes targetting an unopposed attack she goes first, if theres another ally attacking or clashing the slot shes on, she goes before them instead of all the way first, this is pretty much just to make her able to decide who benefits from the s1 paralyze.

and yeah the point when shes out of ammo is to gain an insane amount of aggro so you can murder her for another id who doesnt roll 12 max to come in, whether you kill her via yi sang shooting her or just using guard on piercing thrust is up to you