Ritsuko’s mouth is smiling but her eyes look lonely.
RITSUKO:“At living.”
KnightmareX13: Oh, that was a let down.
Kendrix: At this point, she's wishing Gendo was a little less "clumsy".
UrsusArctos: Ritsuko really seems sympathetic to Rei (and Gendo) at this juncture. And that line probably says a lot about Gendo's own living conditions. Well, maybe not as squalid as Rei's apartment, but I'm sure it's no more inviting.
Sailor Star Dust: A sense of pity for Rei (and Gendo), perhaps?
Cody MacArthur Fett: At first Ritsuko's statement seems to be a reference to Rei's rather insulated social habits, but the statement becomes much more frightening in episode 25 when we find out that Rei is borderline suicidal:
TEXT: "It frightens you, doesn't it?"
REI 3: No, it makes me happy. Because I want to die. What I desire is despair. I want to return to nothingness.
