More sensibly, tossing out one batch at a time of less than 5% of the market will allow the stock to clear without sinking the market.

So parcel up the 2M into 50 groups of a few tens of thousands and we are cooking with gas.

The average trade volume is as you say 4.45M shares. Selling an additional 1.4M raises the daily trade volume by 31.4%.

Economics is supply and demand. If you increase supply by a massive amount when not changing demand. The price tanks. Effectively you are killing your own price point and this sales strategy isn't in your favor.