Lots of games get played.
The seller of 500K could well be a buyer.
He/she puts a large sell order into the market and hopes that suckers or nervous nellies will rush out sell orders under the big 500K one.
At the last moment the 500K 'seller' pulls their order and gobbles up all the low offers.
Or they could just want out, but it wouldn't be the greatest piece of trading to do it in one line on open.
