No matter where you want to work as a Doctor, you need to appear for NEET. NEET is the mandatory entrance examination for admission to Medical,Dental, Ayush and Veterinary Colleges across India. For a Candidate belonging to SC category, you will need atleast 500 marks in NEET. On the other hand, if you can get a seat in AFMC, you can still work in the Navy as a Doctor. In 2019, the cut off for boys was 596 and for girls it was 610. So you need to score atleast 625 to get into AFMC. Alternatively you can complete your MBBS in civilian colleges and then appear for SSC and then you can also work as a Navy Doctor depending on the opportunities at that time.