My client had a memory come up during her subconscious channeling/HMR session that felt like a Nazi slave camp experience. Was this impression correct?

Your intuition is working perfectly and your sense of this is accurate. She was in the Holocaust as a victim in her past life. This is a big part of her issue currently in life and this session will be of great help to her. There are additional things that will likely be needed but this is a great beginning.