The urge to rush right over there and grab the rope was strong, but Dinah didn't. She didn't think that Huntress would let the guy fall-- really she didn't.
And as Huntress said she had this, Dinah shrugged and kept quiet. For now. She moved a bit closer to the action -- all the better to make a sudden lunge for the rope if it did give. She hoped the goon would confess what he knew so he could be hauled back over the side of the building.