existentialism becomes a rogue epidemic
despite the best efforts of governments to quarantine philosophy departments, and decontaminate libraries of No Exit the rapid spread causes intense brain damage as many crawl themselves into fetal positions calling out on their percieved existences. All development will cease as language devolves into demented circular logic, and those stoics who survive will be paranoid of anyone. the lack of collective moral ethos will fostor chaos and anarchy, when combined with mental laziness, the world collapses in a matter of days.
survivor 1: let me in! let me in!
encampment gaurd: no you might be an existentialist
survivor 1: im not, what if you are?
gaurd: how can you prove that i am an existentialist?
survivor: how can you prove that you are not an existentialist
gaurd: Because I have chosen that my destiny will not involve existential thoughts, and i will not abide by some survivors definitions
gaurd 2: WE HAVE A BREACH WE HAVE A BREACH! TERMINATE GAURDPOST 032. I REPEAT TERMINATE GAURDPOST 032!
in all seriousness, probably the dies the fire one