I'm just finishing reading the third book again, and I think the girl who looked up, while possibly referencing a specific person, is also a direct reference to humans leaving shinovar for the first time. The wall is the mountains, and the light is the stormlight, and the darkness is the deliberate loss of knowledge about investiture that I'm assuming happened when humans settled on roshar. Someone crossed the mountains and witnessed storm light and brought it back to shinovar. I think that might also be why the shin have specific prohibitions against stepping on stone, because it would make it impossible to leave shinovar without doing so.
