While “AICO” is off communing with “Aiko”, Sagami decides that his team will help Yura carry out the mission by helping him return AICO’s artificial brain with the Matter. In doing so, he basically concedes that AICO is an artificial being and thus expendable, or at least her sacrifice is instrumental in ending the Burst.
Kazuki isn’t okay with that. Artificial brain or not, he’s fallen for AICO, which Kazuki says is “based on a misunderstanding.” But just because Yura created AICO doesn’t make him the arbiter of who and what can and should be preserved.
While looking for AICO, Yura ends up engulfed by a Human-form Matter, which turns out to be controlled by Yuzuha. She recreates the mountains they once visited to beg him to help her find her body.
All this time, she’s been reaching out to the humans—not AICO—in order to make a human connection. Her body is at the hospital with her father, but she has no scientific data or even anecdotal information for Yura to use to be able to science a way to save her. It’s a very unfortunate situation all ’round.
Meanwhile, AICO makes contact with her real-brained counterpart in the purple/pink Matter. Aiko heard Isazu’s address, and knows an attack from the military is imminent. To that end, she asks AICO to find her family and get them out of harm’s way ASAP.
What about Aiko herself? She believes her “time is up”, and that there’s no longer any time to save her family and herself; and given a choice between the two, there is no choice. She resolves to suppress the Matter as much as she can to facilitate the task she gives AICO.
More interestingly, while existing as the Matter, she felt like she began to lose herself, but has been able to hold onto herself due entirely to her Dream Contact with AICO. Her artificial duplicate has lived her life in her stead, and she’s been able to watch and feel everything she’s felt, the good and bad, thus keeping her human.
AICO doesn’t like the idea of leaving Aiko behind, but ultimately she accedes to her wishes and hurries to where her mother and little brother are being held in stasis.
The resulting emotional reunion is an austere yet surprisingly powerful scene the show successfully earned. Artificial or not, AICO is pretty much Aiko, and rescuing her family has always been a higher priority han rescuing herself.
As the Divers deal with the increasingly dormant Matter, Aiko manages to free Yura from a panicked Yuzuha’s grasp, and Yura races to the cocoon, just as AICO takes her leave of her family. From the look of her, she seems particularly resolved to doing something that will probably result in her own sacrifice.
After all, while Aiko’s need for AICO to act in her place to save her family is all well and good, nothing about those wishes addresses the issue of the Matter itself. Will Aiko or AICO have to die to end it, or is there still a way to reunite them, which could also reunite Yuzuha with her body?