If you take up a medical college this year and leave your seat the next year, then you’ll have to pay a certain amount signed in seat leaving bond (5 Lakh in Madhya Pradesh) (10 Lakh in Maharashtra)
Also leaving the medical seat will make you INELIGIBLE to get admission into any Medical Institution in India for the next 3 YEARS. (This is also a rule in Madhya Pradesh) (For other states, check their DME site)
Seat leaving bond amount may vary, but to the very best of my knowledge,this bond is present in all colleges.
You may check this for different states from the MCC Counselling site, under participating institutions–>Bond.
See the reason for all this is that Govt. spends a lot money on every medical student , both from private (i heard about 12 lakhs) and government (a lot more :P) college.
So you cannot simply leave college next year for other college simply putting a medical seat to WASTE.