I think Ayn Rand would agree with you on this one. In a sense, the person in the concentration camp would not really have a human life, at least with respect to his own moral decision-making. Suicide would not be sacrifice for him. I don't recall. I specifically recall Ayn Rand saying that human life and happiness are two aspects of the same achievement.
Happiness is the emotional reward of a successful human life.
On the wrongness of murder. No, of course not. Hitler was an evil to his own rationality, sociality, independence, sense of life, etc. And yes, I notice that you basically agree with me just below. Actually I would say that the concentration camp scenario is the most likely candidate for the greatest of harms, although it may be exactly on par with murder in some ways.