buys v sell

Here's something I don't get:

ERG buy orders are in excess of 641,[email protected] plus a big backlog all the way to .20c

Only a few thousand SELLERS sitting at .215, with most orders sitting higher. The list of buyers from .20-.21 are higher than the sellers.

I know that this is only what is ON SCREEN and obviously doesn't tell you the whole story, but it must still indicate SOMETHING...

Here is what amazes me:

Despite over 641,000 buyers @21 and only a few thousand sellers @215, someone chooses to sell DOWN into the 641,000++ buyers at 21 rather than be picked off @215 !!

(This was over twenty minutes ago when I looked, so it has probably all changed by now).

Why would you sell DOWN in this situation? I just don't get it. How can it move from THIS situation DOWN to a lower level? What information am I missing here that I find this hard to understand?