I have come across several accounts of children who tried to run away from Craig-y-nos, were caught and punished.
But only one who actually succeeded.
In fact she was a young woman. Her "escape" was remarkably easy: she simply walked out with the visitors and caught the bus home, a journey that took several hours and across the mountain range of the Brecon Beacons.
But it was dangerous thing to do because if you ran away then doctors would refuse to treat you. In the case of Eileen Hill though the doctor ignored the regulations and continued to treat her.