I guess they are the ones who are impatient. maybe they want to make bitcoin prices down, so they can buy bitcoin at a bargain price. Well, I was also surprised to see the price of bitcoin down very quickly. I do not think they could sell their bitcoin under $ 800. but, maybe they have a bitcoin very much, and had to sell in large numbers.
as you know china is owning nearly 90% total bitcoin in the world. why we don't consider this big amount? and they can control this market. Everytime china has any bad news about bitcoin then the price is going down deeply.