Sarantini:
This may be a dumb question but how would you exactly escape from concentration camps like Auschwitz?
There were many accounts of escape from death camps, concentration camps, and satellite labor camps. They were not significant as a percentage of prisoners and forced laborers, which numbered in the millions.
For example, the US Holocaust Memorial Museum, in its database on each survivor account has a criteria for tags labeled "Other Experiences" and under my uncles it lists: "Prisons" (perhaps a reference to the Gestapo HQ in Lyons, "Concealment of Jewish Identity", and "Escape from the camps". IOW it was certainly a thing.
I know I have heard some in my time. (I knew a lot of survivors, in fact now that I think on how the US only allowed some 150,000 to enter after WWII, the number I knew or encountered seems huge, being in the 3 figures. But then I grew up in NYC.) In one, the mother of a friend had been left for dead in a not-yet-filled pit of bodies from which they escaped overnight. They had to lie still for hours among the dead until the opportunity to flee came. Many of those survivors then had a second challenge, to escape not just recapture, but to escape being killed by civilians in the area, even if they were in occupied territories like Poland and the Ukraine.
There is also an upcoming special on PBS about the rebellion and mass escape from Sobibor.
http://www.pbs.org/program/escape-nazi-death-camp/
Some survivors never spoke of how they escaped. That includes my uncle. But perhaps he did in the end. I just found that there is a multi-hour interview of him at the USHMM and I have ordered a copy.