I dont think A2 has a back up since her series is outdated and (spoiler this later>) Yorha sent them all on a suicide mission and cut them off, of which A2 was the sole survivor. More like 2B pulled some strings to get A2 a healing bay, the Nurse!2B is a reprogrammed 2B backup or just another Type B model.
On the topic of why they both look upset at the sexy times: 6O looks like she's about to kill A2 for taking advantage of her personal 2B slave, and Real!2B looks like she's ready to kill everyone; 6O for making a sex doll of her, A2 for getting tricked by a dupe, and Nurse!2B for seducing her A2.
edit: Actually, in the context of this comic, it looks like 2B is angry at the fact a sex doll version of her exists so she's going to destroy it, and she's only partialy mad at A2 for getting tricked. Seems like she's just going to murder A2 on sheer principle. Considering the events of the game, I don't blame her.
last edited at Jul 11, 2018 8:37PM