You really should have an answer for this - most schools will have a question along these same lines, and you will have to prove in your interviews as well. They don't just care about why you WANT to be a doctor - they want to know why you SHOULD be a doctor, why you would be an EXCELLENT doctor, what qualities of yours are unique and interesting.
Think about the qualities of yours that would make you a fantastic doctor and give them examples from your past where you have used these qualities in certain situations, and discuss how these qualities of yours would make you a good addition to the entering medical school class.
no, friend. I asked "why pick us".
not "why should we pick you?"
thank you for the response, though.