Arpeggio of Blue Steel -Ars Nova-/Tear Jerker

"I-402: What is the problem, 401? Iona: Because you...my sisters...will cease to exist. I-402: You simply engaged enemies in combat and sunk them. That is all. Iona: But... I-402: That is all."
 * After Makie learns that her new (and, at that time, only) friend Haruna is the mental model of a Fog warship, she flees (with Kirishima's teddy-bear form, not knowing she's a mental model as well). Haruna thinks it's because humans fear and hate the Fog, and resigns herself to sacrificing herself to allow Makie to escape.  She suffers serious damage from the pursuing soldiers because she refuses to deploy her lethal weaponry, even though it would make short work of them, because Makie wouldn't want her to be that way.  Then, we hear Makie's side of the story: she's not afraid of Haruna at all -- but she thinks that she doesn't deserve to have Haruna as a friend because she designed the vibration warhead intended to kill the Fleet of Fog, so she runs away to draw the soldiers after her and let Haruna escape.
 * Kongou's imprisonment. In short order, she learns that she's been betrayed by her flagship despite her devotion to the Admiralty Code, she's been "infected" by human nature despite her attempts to avoid it, and her remaining subordinate Maya (the closest thing she ever had to a friend) was actually spying on her the whole time .  In the end, she's left alone in the middle of the ocean, with nothing but Maya's broken chattering to keep her company.
 * The deaths of I-400 and I-402. Iona tries to dissuade them from fighting her, but to no avail -- I-400 prevents I-402 from touching her (in the Concept Comm System), as it would risk their integrity.  Nevertheless, 402 seems to show the beginnings of emotion during the battle, moving to take a torpedo strike that would impact 400.  At the end of the battle, however, she still has no idea why Iona is crying over her and 400's destruction, and Iona is left with the memory of what her sisters could have been if they'd been allowed the opportunity to grow as she had.