Yes, but the best way to sell USDT is via crypto legs: buy BTC/USDT and sell BTC/USD - the net result of this is selling USDT/USD. The actual USDT/USD markets just aren't real/deep enough.
So the price in USDT terms skyrockets and the price in USD terms craters.
I'm just wondering, now that they have USD, after selling BTC, what do you think they are they going to do with the USD? It's not like they can extract easily USD from Binance or KuCoin (two of the most popular asian crypto exchanges, where USDT is also the most popular). As I alluded to in a comment above, the reason they are using USDT in the first place is because they can't deal with USD (or fiat) easily. So do they go into some other stablecoin, or keep it in BTC (or ETH), and try to move that to another exchange which is better suited as a fiat gateway? What if this other exchange is a heavily KYC'd exchange that they don't have access to in their jurisdiction, or that it would take a long time to get access to, even if it is available in their jurisdiction? There's also fiat withdrawal limits to consider, which are generally lower than crypto withdrawal limits. Also, to even be able to withdrawal fiat, instead of crypto, requires even higher levels of KYC, more processing time, no guarantee that they will be approved, etc. So, what do you think they will do then? This is also what TimeBearingDown was referring to in a sibling thread.
So the price in USDT terms skyrockets and the price in USD terms craters.