You go to an OTC desk in China, you buy Tethers with $1M USD worth of RMB, you send the Tethers out of China and cash them out either directly at Coinbase or via BTC. [1]

There's been a big market for escaping RMB capital controls since they were instituted, often via various gangs and casinos [2]

[1] https://twitter.com/patio11/status/1424897022268645379

[2] https://www.casino.org/news/us-marshals-service-to-seize-imp...