I think Zhao Yunlan recognized that CSZ was already punishing himself, and adding more guilt at that point wouldn't do any good.
Oh yeah, that too! I had it in my notes but forgot to type it up. *g*

(1) he had to eat a very large number of people to get out of the pillar, and (2) people walk by the pillar on a regular basis. However, Sha Ya and her friends thought they were lost when they found it - an intriguing contradiction.
I think it might be off in the boondocks but near enough to a nonstandard route from one population settlement to another that people do pass it by? Or some other "people do pass by, but lots of people don't know it exists" sort of arrangement.