Let's say an elderly person has a DNR due to a heart condition or something. They are walking down the street and get hit by a car and their leg is broken -- what then? Should they be left to suffer in agony with a broken leg? The trauma will surely kill them, but it will have NOTHING to do with the heart condition. DNR means "Do Not Resucitate" as in "Her heart has stopped. Start CPR and call a Code Blue".
It does not mean "Do Not Remove from street".
Until her heart stops ..... on it's own, ...... you still have to treat them like any other live person. Them's the rules.
Monty Python: Not Dead Yet