Rei, unlike her canon Mysterious Waif personality, is a master-class abusive Deadpan Snarker who does not put up with Shinji's shit.
Shinji: So they expect me to pilot it again? Really?! After all I've been through?! After all the pain?! They just want me to-
Rei: You know what you need to do?
Rei: Get some tampons, drink a bit of cranberry juice, and go see your gynaecologist. I think you're starting to menstruate again.
Shinji: So you really don't care if they just use me or you to pilot until we die?!
Rei: I want you to do something.
Shinji: Uh... Okay...
Rei: Look at my face.
Rei: Just look at it.
Rei: No, no. Keep looking.
Shinji: I am looking!
Rei: No you're not. Look harder.
Shinji: Is there a point to this?
Rei: Yes. So look as hard as you can.
Rei: Focus on every part of my face.
Shinji: Alright, alright, I'm doing it!