sometimes when people miss the bid price while they're chasing the market, that does happen. But the bot trading is high amounts of bitcoin at satoshi levels that are not of any psychological significance to normal human trading. And as the price continues down strategic buy and sell orders are put in to maximize profit. Its usually just enough to make it seem like the market is going to turn around and go back up. People get tricked in to getting back in, and it sells again. Its a very sneaky but effective way to trade.