With their first couple of spells missing their targets, but realizing they could cast their spells outside the barrier as long as they were close to it, they began to unleash them as fast as they could scry them. Lilu was adept at forming the mana bullet spell, and was forming them 10 at a time. Macky was also casting her spell back to back without stopping.
Little by little, the sheer volume of magic being cast towards the direction of Juan insured that little by little the Goblins around him were getting hit. Lilu had tried to use her target ability, but there were far too many, and she couldnt get a clear enough and steady enough view to lock on. As such she had to use the method of accuracy by volume.