I certainly can understand why you may fear to have an IN-PERSON PLAY exam. Perhaps a few thoughts from an experienced medfet play doctor to those of you considering a real life experience.
1). Take your time in getting to know your potential play physician. Are they responsive to you promptly? Are they willing to answer you in a way that feels honest? (Remember the questions you are asking should be addressing your fears/concerns).
2) Can you find others who have made appointments with your medfet doctor? If there is a track record you can look into? That can help.
3) In your discussions with your medfet physician, do they sound "professional," "knowledgeable," "experienced," and/or "comfortable"? Use your intuition here - you know what you are looking for and do NOT, even for a second, hit the YES button unless it feels like that is the right thing for your needs. It is OKAY to ask if it is their first time as a medfet doctor/patient. We are all newbies once!
4). Are YOU clear to your medfet physician on your expectations? Never hesitate to be explicit in what you are looking for, what your triggers are, what your limits/boundaries/absolute NO-GO situations. If need be, create a small document/contract for you both to agree on. Granted, this cannot be a legally enforced document, but it may help ward off "undesirable" behaviours. (Check the web for advice on drawing up such a "contract" - there are plenty of excellent BDSM sites that offer great solutions).
5) Before meeting "in the flesh" - try to arrange a meeting virtually - things like Skype, Google Hangouts, etc. offer protocols for seeing the "other" while remaining in a safe space. Consider this is you are unsure.
6). If practical, meet in a public area WITHOUT the pressure of playing. There are lots of safe public spaces where you can talk over the scene and still get a sense of whether or not the person you want to play with is within reason.
Sadly, we live in a world where meeting others can be dangerous. MedFet often involves feelings of anxiety and humiliation - this is not the thing that should prevent you from actually playing out your fantasy. Instead, your goal is to trust each other in fulfilling your role-play obligations. Do all you can to vet the meeting and even after having done "all you can," you have to remain on guard. Yes, you might still have a "bad" experience.
If you are anxious about something other than your role-play partner in your medfet play, I suggest you think about why you have those feelings. Do not let generalised anxiety stand in your way. Be sincere and honest with yourself.
I encourage you to explore your medfet fantasies as a healthy way of self-understanding and realization.