interventions

This is relating to a charge nurse that I was working with that had received lab results on a patient and decided to call the doctor to change the patients amount of Coumadin that he was to receive later in the evening. The charge nurse did not ask for the MAR so that she could see what the order was originally, so when I got the chart and saw that the amound the patient was going to receive was going to be twice the amound, I did not think that was correct. I took the chart along with the MAR to the charge nurse and told her to call the doctor back and fix the order because I was not going to transcribe the order and cause a life threatening incident to take place. Now if the charge nurse had come and asked to see the MAR before calling the doctor then she would not have had more work to do. I feel that this was a result of deductive reasoning. If I am wrong please let me know. I think that my reaction to the situation was the correct one and I do not believe that I would have done anything differently in the future. what do you think?