Dr. Warren, it appears, still takes his work home with him.
As was common in his day, the right front half of the first floor of the house, across from the parlor, was his office. It has been converted into guest rooms at the inn. Guests staying in those rooms have been awakened in the night by a dream – the same dream: a doctor looks down at a patient lying on a table writhing in pain. The doctor appears unable to do anything. He walks back and forth in distress. That would explain the pacing other guests have heard outside the door of that very room.