I'd say "impending doom" or "too dumb to live," but it's Mokou.
She has inadvertently killed herself at least once in canon (to the extent that the Inaba manga can be considered "canon")
She mentions in one chapter how she ate undercooked mushrooms and died of food poisoning, although the mushrooms in question were poisonous and it was the poison that killed her. Towards the end of that chapter, she cooks a meal for Reisen, who eats it but suffers no adverse effects (until, of course, she does)
I finally did it to life.
In this case, it's a mocking expression for suicide.
Originally the other way around: Life finally did it to me. A mocking statement regarding the current situation of a certain thing, and blaming life for it.
e.g. (posts two pictures of a cat, the current one is significantly fatter) Life finally did it to my cat.
LifeMe
