There were a very small numbers of "survivors" scraping by on wild plants and small animals. The area is large enough, and has sufficient ruins with basements and semi habitable structures. The Security Force did not bother to look for them, if they approached the Walls, well, it has already been noted that since the first Wall was completed no one gets out, regardless. The number of survivors drops every year as the diseases take their toll, surviving women become infertile, and age takes its toll. By ATL 2001 there are 20-30 left.Is it bad that I kinda want to see some tribes of feral descendants of hardcore Nazis in those zones waiting for the day when their fuhrer will return and once again led them to glorious conquests... perhaps that's the plot of some pulp FPS ITTL...
At one point I was tempted to make an ASB thread of what if all the hardcore neo-nazis from OTL 2010s ISOTed to those zones with their personal weapons and could they have resurrect the third reich to glory again and then I realize it would have been a mass death scenario (to some rather unsympathetic people, but still in bad taste), so I didn't.
Almost no one has ever really suggested that the effort be made to rescue them, it isn't like they were not given literally YEARS of warning that the Walls were going to be built, were being built, were finished and would be closed off with no exit after that time. Even the Stettin revolutionaries didn't have any illusion about what sending in rescue/recovery teams would mean. The heads of various major religions occasionally call for an effort, they may as well try to call of a new Crusade to recapture the Holy Land (actually they would likely get a better response to the Crusade idea, and you could count the number of people who would respond to that without getting to four digits)