I am aware there were over 2 m of shares bought by SO. That could be the reason of the rise in early Q3. And then the selling began and stock price dropped $35. By just looking at the chart you can obviously tell most of the buying pressure was done in July and most of the selling pressure was done in August and September. This is consistent with your selling into recall laid here. But we don't know how many shares were actually recalled. So the amount of recall may not be enough for those who were opposed to the merger (or whatever reason) to sell, and they continued to sell, and the stock price went down.
The problem is that we have snap shot of SO at the end of Q2 and at the end of Q3, and there is no information on institutional SO in-between. You can't associate $35 drop with these two snap shots because the drop associated with these two snapshots was not $35, but as I pointed out only $2. The bottom line is that if you go back and look at the contemporaneous posts, the $220-230 plateau was associated with no shares available to short, and the drop from this plateau, as I mentioned several times now, coincided with the sudden availability of shares for shorting.