Dear Pranav, we dont know if this is a hypothetical question because NTA hasnt conducted the exam yet for admission to  Medical colleges. However, assuming that this is a hypothetical question, we shall answer you. So MCI will conduct atleast 2 rounds of counselling. For example, during the first round of counselling, you get an admission in a Medical college. You have 2 options. You either can take admission and join the college or you can go to the college and surrender your seat. If you surrender your seat, it is called free exit and you can participate in the 2nd roumd of counselling without any penalty. But you join the college and after the classes begin, you want to give up your seat, then it is too late because the counselling would have been over and you cannot attend any counselling.