" Not for anything in the world. How could such a thing be" ?

“不是为了世界上的任何事情。怎么会有这样的事情” ？

Not for anything in the world would they return to their old lifestyle, which held them trapped like poisoners in an unhappy world of their own making.

他们无论如何也不会回到原来的生活方式，这让他们像毒药一样被困在他们自己创造的不快乐的世界里。