[You can't run on anger all the time, she says, and Natsuno's first thought is WATCH ME. Anger is all he's left, because if he stops running on anger, it's either sadness or numbness, neither of which will help. At least anger pushes you to act instead of drowning in existential horror.

Then Clarke says kill the Captain right alongside us, and... well. That was always the plan, wasn't it? Natsuno has no intention of burning out (figuratively and literally, considering the captain) and leaving her to deal with it alone.]

You say you can't swallow the sadness, so tell me this. [Part defiance, part genuine question.] Grieving people move on because they know death is final. How can you do it when it doesn't stops?