Post-apocalyptic fiction isn't so much a realistic analysis of human behavior as it is a projection of a culture's values and beliefs.
Take the "Walking Dead", for example. A central theme to that series (TV show or comics), is the existence of safe but tyrannical communities. It is contrasted with Rick's group, who are good decent folk, but are constantly struggling to survive.
There's also Stephen King's classic "The Stand". The "good guys" are disorganized but democratic. The "bad guys" are well-organized, but live in fear.
In Resident Evil (the movies), every form of civilization has collapsed, except the Umbrella Corp, who continue their nefarious experiments in vast underground complexes. This is an obvious reflection of the fear of a powerful corporation in a consumerist society. I'm not sure "evil mega-corp" has as much of a resonance to Chinese audiences.
Obviously, it would be entirely speculative to try to predict what people would really do in the event of an Extinction Level Incident. After all, nothing says "Walking Dead" is an accurate portrayal of post-apocalyptic Americans.
So the real question is, what would a Chinese writer, or a writer with a Chinese mindset, come up with for a post-apocalyptic world set in China?
Or rather, how would *YOU* create such a setting?