This is hilarious. You want to find out about the Egyptians and their beliefs structured around the third eye, read about Egyptians. I'm not gonna sit and read it to you like I'm ******* Mother Goose.
I understand the Egyptians had beliefs about third eyes, but that doesn't mean they understood the third eye to be the pineal gland.
You don't know that, you're just asserting it because it makes sense to your preconceived notions -- but there's no evidence.
Have you considered that they removed the brain through the nasal cavity because -- oh, I don't know, because it's the easiest way to remove the brain without opening the cranial cavity? On what grounds do you assert they had any knowledge whatsoever about biochemistry of the pineal gland?