Nursing Philosophies (moral issue between killing and letting die)

Question: WHat do you think is the main moral issue between killing and letting die? Give several criteria to support your assertion.
Required book: Principles of Biomedical Ethics Seventh Edition Chapter 5. Nonmaleficence by Tom L. Beauchamp and James F. Childress
Work citation from the required book is a MUST with page numbers (MLA style)

You may use additional outside sources as needed