My employee, saw me go into my appointment. She was there, for other reasons, at that point. But considering, I know what she has from being merely co-workers, at one point, I am not worried.
However, I do feel for you. The reality, is these places can be busy little offices, and you'd be surprised at how many people, 'you'd never expect to see in there', are there.
Perhaps, taking the non-challant approach, and if, and only if, it becomes an issue, let go of worry?
Hang in there. That medical assistant, would be breaching the privacy laws, would they not