When interviewers asked me what other careers I thought of pursuing, I was simply honest. At first, I reinforced my passion for medicine and stated that if I were not to gain admission this cycle, then I would improve my application and reapply. But we are all real people, and we all have (and should have) interests outside of the sciences and medicine. Certainly everyone who is realistic understands the value of evaluating other career options, and for me this other career was being an English professor & freelance writer. I love English, and I was able to make the choice to go into medicine through my clinical and volunteer experiences. But I still enjoyed English through taking lots of English classes in undergrad and editing newsletters and writing short stories, something that I can do as a physician also.
So, my advice would be to state that you have through your multiple experiences firmly established that you want to pursue medicine. But before this became clear, you explored (insert other fields that genuinely interest you, may even be hobbies).