According to Mercutio's logic Queen Mab makes men and women dream about their deepest desires. Lovers dream about love. Lawyers dream about making money. Ladies dream about kissing men. A pastor or leader of a church dreams about large donations being made by his congregation. Soldiers dream of efficiently killing people, and virgins dream about sex.
By that logic, a doctor would dream about saving hundreds of people from a disease. If the doctor were a surgeon, the doctor would dream about performing a flawless operation on a patient. Perhaps that doctor would dream about giving a lecture to a room full of other doctors about how best to treat the ill. Perhaps the dream is about making a medical breakthrough that will benefit all of mankind.