"I have never been a queasy individual, and I fully understand the types of cases I will see in my career as a physician. I work part-time at our local drop-in shelter and have seen many situations involving blood and other body fluids. Rather than think about the gore, I remember that it's a human who needs my help. I believe this mentality will get me through any gruesome or undesirable situation as a medical student."

You can keep your answer simple by discussing your ability to handle events involving blood and other bodily fluids. If you have direct experience with these things, now is a great time to discuss that experience and your ability to handle it. Make sure to reiterate that you are aware of these harsh realities of your future and that you are ready to manage anything that comes your way as a medical student.