These environments show an alternate reality for the Egyptian soldiers drowned during the Red Sea crossing by Moses and the Israelites.
Osiris – the Egyptian god of the dead – was moved by their situation, once they were dying underwater like himself. So, with the help of Anubis – god of embalming – he decided to keep them undead in a place built exclusively for them under the Red Sea.
The second environment shows the chamber where the Book of the Dead is found.
I hope you like it!