As I recall, the memory hierarchy was actually simple--the issue was that it called some structure_free(parent) in C++, which freed the entirety of that part of the hierarchy--the parent and the children; which would obviously cause problems if the children weren't done working.

That said, I'm looking over my backups from that era; I can't quite figure out what real code corresponds to the pseudo-code in the post (I didn't have the real code when I wrote the post).