Seems like that's exactly what the OP is trying to do, using the loan as a hedge:

1) BTC goes down, OP repays devalued bitcoins, walks away with the USD, the cost is only the tiny bit of interest.

or

2) BTC goes up, OP walks away with bitcoins, leaves the lender with the collateral USD.

That's assuming the loan is denominated in BTC. If it's denominated in USD then it doesn't make sense to begin with, because the OP already has the USD.