Really cannot say I ever noticed that, certainly not in this situation. Definitely triggering off of it entering the room which almost makes me think its a type of alert/danger sense... I don't know off-hand if banshee's normally sneak (but doubting it?). Later in the fight, the spirit wolf has no problem assisting me... just wish I could recall if it ever did exactly that for anything else (but if it had happened more, I think I would have remembered then..huh)