Aerdrie saw the goblins closing in on Dean and with a quick scan of the surroundings saw that Riq and Sol seemed to be successfully keeping the waves from entering between their powers, but the ones who had already made it into the camp with Nevermore, Khana, and Mogget were fresh pickings. Still, she'd always been excellent at prioritizing, perhaps that best explained her easy and solitary survival.
She let loose a quick stream of arrows finding it easier at this distance to aim and quickly put shots into the ones approaching Dean, seeming to very easily intuit not only what Dean was going to do, but also what the goblins were going to do so that she never put an arrow in him and always kept the goblins from sticking him. Certainly, there were several times he watched an arrow slide by his arm a hair length from hitting it to embed itself right between the eyes or chest cavity of a goblin, but it wasn't anything he could easily complain about.
Still, her arrows were not infinite like the powers of the others and soon she was forced to leap from her perch to join the fray with her rapiers. As she worked, she called out to Nevermore, "The Big Goblin, kill the Big Goblin. They're a very cowardly bunch. They won't fight with him gone. " With that, she was swallowed back into fighting