They didn't loan him $1,000,000 all at once. The person used as an example initially borrowed $601,506. That seems high since he was told to expect the program

They didn't loan him $1,000,000 all at once. The person used as an example initially borrowed $601,506. That seems high since he was told to expect the program to cost $400,000 to $450,000, but the original WSJ article explained that unlike normal medical residences, dental residencies typically charge tuition, which is another 3 years of loans on top of the original 4 year program. After the residence, he took a year of forbearance to get established. Of course, for all 8 years, the interested kept accruing. From the $601,506 starting point, the $1,000,000 comes from him paying less per month than interest rate thanks to a government program he is in. He pays $1,590 while the debt grows something like $3,900 a month, so he isn't even trying to pay off his loans currently. After 25 years, the program he is in has the federal government paying off the loan, which at that time is estimated to be about $2,000,000.