The difficult part seems to be getting someone lending you $1m in USDT, isn't it? From their POV, you're getting exposed to BTC volatility, and the collateral is likely to be too high to make this practical.
Basically, how do you buy $1m worth of BTC/USDT perps without depositing $1m of USD into Binance? Let's say if we put in $100k USD with a 1:10 leverage, it means the position on Binance is wiped out if BTC drops by more than 10%. So the only way for this to work is to deposit $1mil of USD into Binance and opening the position. But this means we lost a whole $1m when Binance implodes, cancelling our gain in the short position.
Otherwise, we need to borrow $1mil of USDT to open the Binance BTC/USDT position.
On May 19th, Binance froze up and prevented people from adding margin. Lawsuit about it now. The claims are that Binance was insolvent and redid the trades to stabilize themselves. See Frances Kim for info or an FT article about the lawsuit.
Whatever the reason, no guarantee you can deposit collateral.
Nobody is lending us anything in the above example (well, Binance perps and CME futs have embedded leverage but that’s another story).