The beauty of Medical profession is that you can work at your own convenience. There will be emergency situations and that cannot be avoided. But if you are working for a multi speciality hospital or a super speciality hospital, there will be more than 1 doctor for each specialisation usually and you can then work on call. But when you just start of your career, this might not work but as you said after some years, you can clearly work as a consultant at your own leisure. You are not bound by any contract unless you sign one with the hospital that you are working for. Many doctors do the same thing.