I was considering the same sort of angle for an essay. It was recommended to me not to name the physician that did not do X, Y or Z as an MD or a DO, but just as a physician.
Instead of saying "While watching Dr. Allo, I noticed that he did not do this, and I wondered if Dr. Osteo would have done some manipulation thing... I realized that I wanted to become a DO like Dr. Osteo."
You could say something like "While job shadowing a physician, I realized that I wanted to become an osteopathic physician because in a situation that I observed. I think that this sort of manipulation would be able to make a difference in the outcome in the treatment of the patient. I would like to be able to offer that sort of treatment to my patients when I become a physician."
The second example does not disrespect any physician, MD or DO. It also does state one reason that you may want to become a DO as an added bonus.
I hope I helped you and your question. Unless, of course, you are competing with me for the same seat in a school where I want to go.
Good luck with your essay. Make it great!
dsoz