my future as a health professional
my idea of an improved health diagnosis system
These are unique responses and direct qualifiers for your double major. Why not make it more definitive so that the reviewer will have a stronger idea of your course and university choice process. These actually tell the reviewer more about what your interests are and how Waterloo applies to your professional purpose, which is the point of this prompt. It is important that you enhance these aspects of your response so that you come in strong with your written interview response. Remember, this may be the only chance you will have to convince the reviewer that you have a qualified purpose for attending Waterloo. Focus on the strongest aspects of your response.This is a unique presentation that can create an impression on the reviewer, if properly developed as a response.