ok i'm lazy rn so basically on scenario Φ a bunch of things happen to the earth that cause a bunch of simultaneous disasters. also a bunch of life suddenly multiply. and there's a virus going around that causes gigantism. The event usually happens every 100-50 years and ends after 5-1096 months. phi-bunkers are very big bunkers that are very versatile. once the weight limit is reached, people may not enter. the doors close, and the room scooches back a bit, and a bunch of springs are attached. this is to decrease earthquake damage. small problem, they're very hard to maintain, and some cities only do maintenance on it half as much as they should, sometimes never; people have died because of this.
