If a doctor asks you to wait in the wait outside, just say calmly yet confidently, “I’m going to stay out of the way, but I need to be here.” Then back away from the patient to the side of the room where you are out of the way.
If they ask again, just respectfully say that you promised the patient you wouldn’t leave them and you won’t interfere. Stay respectful and non-threatening.
Sometimes, the patient may need to help by speaking up. Most doctor’s will not oppose the patient’s wishes.
If you come across a particularly difficult doctor, you may need to talk with the hospital’s patient advocate, or the hospital administrator.
Do what you need to do to stay and be an advocate for your loved one.