I think it would be a good story for your midterm! I would enjoy it if it was for my class. Why is Hans killing Rosa though? If she's in the concentration camp, won't she just die there anyway? Or if the nazi people are the ones who want her dead, why would they tell him to take her to the woods to kill her instead of just killing her in the camp? I just think it might be lacking in character motivation unless you left something out.