Interesting question. Bottom line - you'll be able to get rid of your prior loans after 120 payments, but you'll start a new 10 year clock on your med school loans 6 months after graduation (assuming the program even exists in its current form then), so you won't leave residency debt free, unless you don't borrow for med school.
If I return to school and qualify for an in-school deferment on my Direct Loans that are in repayment, can I decline the deferment and make qualifying PSLF payments while I’m in school?
Yes. You can decline an in-school deferment on your loans that are in repayment status and make qualifying payments on those loans while you are in school. In this case, you must contact your servicer and request that the in-school deferment be removed. Remember, in order for your payments to qualify for PSLF, you must be employed full-time by a qualifying employer while you attend school.
Note: If you receive new Direct Subsidized Loans or Direct Unsubsidized Loans when you return to school, you won’t be able to make qualifying PSLF payments on those loans while you are in school. Any new Direct Subsidized Loans or Direct Unsubsidized Loans you receive won’t enter repayment until the end of the six-month grace period after you leave school. Although you could voluntarily make payments on your new Direct Subsidized Loans and Direct Unsubsidized Loans while you are in school or during your grace period, those payments wouldn’t count toward PSLF.
Can I waive the six-month grace period on my Direct Subsidized Loans and Direct Unsubsidized Loans and begin making qualifying PSLF payments early?
No. The law that governs the Direct Loan Program does not allow borrowers to waive the grace period on Direct Subsidized Loans and Direct Unsubsidized Loans. You cannot begin making qualifying PSLF payments until after your loans have entered repayment at the end of the grace period. Any payments you make on a loan during the grace period will not count toward PSLF. However, if you want to immediately begin making qualifying payments on your federal student loans as soon as you leave school, you may consolidate your loans into a Direct Consolidation Loan during your grace period and enter repayment right away.