I think your right about MM manipulation. It defies logic that anyone is dumping big blocks of stock in the midst of the slew of positive and productive press releases which are going to continue, IMO. And I have also noticed the 100 share moves at the last moment, except it didn't come before the bell this time. I believe the MM's are starting to smell the break-out coming soon and are doing what they can to get investors to dump shares.
Its obvious market makerswere the ones shorting it , they did not want to see it close green cause they would have a margin call they all bet the stock was going to go down , but the company is not diluting so I feel bad for anyone who is short MDOR