From a trading perspective, it absolutely was a mistake. What are the clues.
1) Still NO NEWS out.
2) The shares happened in one push down. No follow through at all. Selling a 1/4 million shares of ATRS is not all that tough. So, I can find no reason to give up $50k when you could work the order easily in one day without dropping the stock .30 cents.
3) 50k bid posted @ $3.63 now. (Little fear of buying)
***I am putting my money on a "Fat-Finger" mistake. Another option I like less but one that is certainly possible is a block trader simply had to pair off a trade and wanted to get started on his weekend. Either way...we had hit a wall of consolidation @ $3.80 and somebody decided to unload. They just did it like an IDIOT.