I have a hunch. I'm sure someone else must have had it before me.
Note that Anna's never had a real medical checkup since the UN found her.
I don't think that the Anna you control in this thread really is her. I think that the Suit is the character we're controling, that the little voice that leaves messages for us is part of all that remains of her.
Which leads to the following bad end if it's true... Someone or something forces Anna to desynth, leaving a body who's mind is still that of a little girl (maybe leaving no memories from after she found the suit in the first place). This would be what I'd expect if Anna became the OTP.
(edit) Ah, yes. Not the only one indeed.