how had davids mother escaped from the concentration camp?

There is a commandant who cares enough about David to make sure that he has access to food and even vitamins and one day, inexplicably, sets up an escape for him. He hides a get-away bag for him outside the fence and turns of the electric current in the face momentarily so that David can escape.

According to the book "the man" was in love with David's mom and then arranged papers to send her away from the conceration camp