At the moment of collapse there simply was not enough buy orders in the books for liquidation engine to sustain offloading.

Here is another, more in-depth rumour thread on how BitMex could have influenced the BTC rektage 👉 https://twitter.com/lowstrife/status/1238818943147507713

The original post was by Alameda (FTX): https://twitter.com/SBF_Alameda/status/1238306306043162625

In a nutsheel, the argument is: risk was calculated poorly and allowed to hudreds of millions to be liquidated at once while the book had 0 depth. So when you said before no one could have sold that much BTC, why - this is actually true. It was degen leveraged positions causing harm to everybody because profits & insurance fund are also in BTC.