I know everyone has a story, here, but I knew several survivors when I was younger. The "general" answer is that the few that survived were highly exceptional —

I know everyone has a story, here, but I knew several survivors when I was younger. The "general" answer is that the few that survived were highly exceptional — they Nazi machine wasn't perfect. So, most of them had stories that were really over-the-top & full of coincidence. Everyone who had a normal story was dead before the war ended. One of the survivors I knew was executed twice. He said "it didn't catch".