I had been watching that 10 million on the bid for a couple of days. It started out in the .002's. Yesterday, it first got hit for a small portion at .0032, so it dropped below 10 million.
Then it was reloaded to 10 million, and finally raised to .0034. One of the things I was pondering was whether it was a real attempt to buy, or if perhaps it was a seller trying to show large bid support while selling on the ask.
When it got filled, I knew it was a buy. Now I'm watching to see if the seller is gone, or if he tries to get back in. I suspect he thought he could buy back lower and come out ahead.
So far, there haven't been enough sellers to let him back in. I hope it stays that way. Sellers need to be left behind: they just get in the way of progress... ;-)