The situation Lynnabelle has described happened to me last Christmas- I was losing the sight in my left eye and was rushed to A&E. After a junior doctor examined my eye he immediately called the senior doctor, who called an eye specialist, who came from his bed about an hour's drive away in the middle of the night and during the hours that followed, saved the sight of my eye.
Inevitably I was in A&E a long time and marvelled as the staff dealt with many drunks who were being abusive, vomiting and being generally disgusting and disrespectful. One of them lost consciousness and the staff leapt into action to resucitate this person. I'd overheard a conversation between a junior doctor and nursing staff and he had been on duty for about 50 hours at that point. After so little sleep, it's amazing the doctor was still standing, never mind functioning in a critical situtation.
Who can perform well after so little sleep? That is how mistakes can occur. It must surely be the way to drive the young doctors to seek better pay and conditions elsewhere. I support them 100%. We need doctors to have reasonable working hours and conditions, so they can give the very best care to patients in need of their education and skills.
(The problems with the drunks in our towns and cities every weekend is another matter of concern.)