The interviewer wants to get to know you. When they are testing to see if you would fit in with the rest of the team, interviewers often ask questions like this to learn more about your interests. If you could have any career in the world, what would you choose to do? Is there another type of job in the medical field you would consider? Or would you pursue your passion of becoming a travel writer? There's no right or wrong answer, just know your audience and talk about some of your additional interests and passions you would love to pursue.