For the greater good.
Impression
I died a little inside when Kotori’s parents were shot. I’ve been dreading that scene for weeks. It was pretty much identical to the VN as well, from what I can remember. Six gunshots, three to the head of each familiar, followed by Kotori’s hoarse scream as she falls to the ground and stares at the disintegrating ash. And then Kotarou says he can’t stand her, that he always thought of her as an annoyance, and that it serves her right. Kotarou and Kotori have butted heads a lot, but this was easily the cruellest of all the things he’s done to her. And in the end, it’s necessary. Nothing less would enrage her enough to make her run as far away from Kotarou as she possibly could, out of the forest and away from all the conflict. Plus, without two of her strongest familiars, Kotori becomes less able to defend herself and the impetus for her to just leave increases that way as well. I love Kotori to bits, and so all this Kotori suffering really hurts, but Kotarou’s doing it because he cares, as hard as it might be for her to understand at the time. You’ve seen how cruel Guardian can be insofar as lolis are concerned. A loli summoner protecting the Key, regardless of whether or not she’s with Gaia, is still a summoner and will be immediately killed at best. If she was found by someone capable enough like Esaka, who suspects that she’s more important than she might initially seem (lolis aren’t usually summoners after all) then even more horrible things might be done to her in an attempt to extract whatever info she knows. Kotarou killing her parents and driving her away to safety is the least painful option.
Come to think of it, a lot of people died this episode. Suzaki’s was fairly emotionless, as Bond quickly realised he’d caught onto the whole triple agent business and had to silence him. And no-one cares about Suzaki anyway. Not even Kashima Sakura (any longer, at least). Esaka’s had a greater impact, although I think the entire boss fight and its aftermath was dampened by how the pacing has accelerated a little too much in recent episodes after dawdling during the initial episodes of Terra. The fight ended up being rather truncated as a result, and there wasn’t as much of an indication (unlike in the VN) about the relationship between this fight and their practice match back at Guardian bootcamp.
It was essentially the moment where all the pieces fell into place for Kotarou, and unfortunately Kagari just wasn’t around to see it after the Song of Destruction started addling her brain. I feel like Kotarou could have avoided that a little longer – like if he had somehow made sure that Suzaki stayed in power, meaning Kashima Sakura wouldn’t make a move and start assembling her choir (complete with a brainwashed Iko-chan) and so Kagari would have stayed lucid. It probably wouldn’t have done any more than prolong the inevitable, though. Guardian would have captured Suzaki at some point, and so long as Suzaki was alive it would have risked Kotarou’s cover being blown. Although now he doesn’t care about Gaia, and technically it’s still in place as far as Guardian is concerned because both Esaka and Oonishi are dead and they were the only ones who knew.