i don't see why you're shocked. they've been doing this almost every day. they short it at the beginning of the day and try to drive it as low as they are willing to risk and as low as it will go without reducing short share availability so their interest rate can stay as low as they are willing to tolerate. Then, towards the end of the day, they start buying back the same shares they shorted in the morning.
Their hope is to drive it very low intra-day to drive out traders who hate to see their stocks down; to cause these traders to dump their shares, so that the shorts can buy them back, or cover, from the morning's borrow.

They play this game, day in and day out since there is no news. They ready themselves at the beginning of the day by being prepared to renew the whole 7.8M shares available in the event they want to create a short attack. If the company puts out good news, but not phenominal news, they will likely initiate a short attack because they would think they could thwart it without very good news to back it. They would Renew all 7.8Million shares available and then short it to try to capitalize on as many pennies as they can x 7.8M shares.

With extremely good news like news of a partnership, they would do the opposite, they would not renew, but rather, they would try to cover as many of the 40M short interest shares as they could, but that covering by itself would drive it north rapidly, not even considering the partnership news.