Here is my advice... evil grin.

Since you will be out of country for at least 4 years (med school), and possibly longer if you stay for internship. Why not use up your line of credit? Then either declare bankruptcy or let the accounts close as charge-off. You will have credit ruined but...

The bad records will stay in your credit file for 6 years. They will have to be removed according to current laws after this period. By the time you are back, you start record-clean as you never had any debt before.

Another way is to marry someone in Australia (if you are not married already). Then get the citizenship, make a name change. When you come back, apply for a new S.I.N. You are a new person again.

The first one is unethical but legal. The second one is neither.

Disclaimer: Above information is based on existing public information such as "creditnet.com". I am not suggesting/recommending/soliciting/encouraging any illegal activities. These are listed as loopholes in current system for educational purpose only. You are responsible for your action/decision.