RITSUKO:“Yes, this is where she was born.
The water and light that form Rei's subconscious
must have a strong impression of this place.”
MISATO:“Dr. Akagi, this isn't what I came here to see.”
Dr. Nick: You'd think these wall and floor scrawlings might be related to medicine/chemistry, but instead they're mostly about quantum mechanics (plus TiD2 being titanium deuteride and 7iD2 being apparently nonsense). These references together with the bookending Reis have led fans to theorize that Rei is a non-linear quantum state being. As nuts as it sounds, it's probably one of the less controversial fan theories!