Here, I’m saying one of two things, and it’s fundamentally unclear which of the two I mean:

• I do not know which doctor I will see, so I do not know the pronoun of the doctor.
• I will see the same doctor I always see, and they prefer a nonbinary pronoun.

Well, there’s always troublemakers like me who would be perfectly happy with confusing their audience in this way :) (considering that the very basis of my identity is “my gender isn’t relevant to who I am, so I’m opting out”)