Yes, to be an army doctor you will go first to Army Medical College after clearing the (NUMS) entrance test.
On successful completion of the MBBS/BDS Degree Course, the Graduates of Army Medical College will undergo 22 weeks of basic military training at PMA Kakul. Female candidates will join the Armed Forces Post Graduate Medical Institute (AFPGMI) for the purpose after graduation.
It's not compulsory to do the MBBS/BDS degree from Army Medical College to become an Army doctor. You can also apply to PMA even after graduating from any other Private Medical College.