If we're open for pure speculation - then I have doubts about an escape attempt. Typically the forced marches were from east to west, so why try to slip the leash when you're going in the right direction anyways? Plus, in winter, in hostile territory -- it's hard to imagine anyone thinking escape is a viable option. Perhaps more likely are summary executions for not keeping up on the march - happened by the thousands for concentration camp inmates on those end-of-war winter marches. I would have thought western Allied PoWs would be a more privileged group, though. That's it for my speculation. Eagerly awaiting anyone with facts.