The Country Doctor

"The Country Doctor" was extremely confusing to me. The story opens with this doctor who needed to leave the village immediately because a patient was very ill. He had no way of getting there because he didn't have a horse for his carriage. Suddenly appears a groom with two available horses who refuses to take the trip with the doctor and prefers to stay with the doctor's maid, Rosa. Rosa was petrified by this being she didn't know who this man was and because he had, I guess, bit her cheeks. The doctor arrives at the patient's house and the patient informs him to just let him die. The patient eventually dies after the two converse but all the doctor could think of is Rosa facing the consequences with the groom back home. The ending to the story talks about a "false ringing of the night bell" and that "the mistake can never be rectified". The only assumption I can make of this is that the false ringing of the night bell was the call to do the impossible -- save a patient that was extremely ill with little chance of survival. And the mistake that can never be rectified, is saving Rosa from the groom.