While luck may indeed have something to do with it, I think that one's MCAT score is generally viewed by adcoms as an objective measure of one's standardized test-taking ability -- at least, that is the goal of the MCAT; whether it succeeds in that goal is a conversation for another thread. I'm not trying to be harsh here, but trying to rationalize your MCAT score by saying that those who score better might be doing so on account of luck may come off as not being able to take responsibility for your performance. This is why I suggested writing about it in the "challenge in becoming a doctor" secondary, as this would allow you to demonstrate that you accept responsibility for your score, while at the same time using your stellar sGPA as evidence as to why you believe that your MCAT score does not accurately represent your true academic potential.
Taking a step back and looking at the bigger picture, considering your high GPA, I don't think your academic credentials are going to hold you back here, which is why I don't think you necessarily have to explain your MCAT score. However, if you feel that you absolutely must, make sure you are able to rationalize it in a logical manner! Again, I hope that this post doesn't come off as too harsh -- just an opinion from an impartial observer. Feel free to PM me if you want another pair of eyes to look over your essay. Best of luck!
