I don't blame you for being angry. A situation like this shouldn't happen. But now is the time for cooler heads to prevail. Perhaps you have a good "smith" in your area who certainly must have encountered this situation before. If I were to insist on doing this fix myself, I would only do so by acquiring some "left twist" drill bits from MicMaster/Carr or Grangers, as suggested above. In the past, when I have used this method, the left twist bit grabbed the broken screw and backed it right out. You may be able to find left twist drill bits at a local hardware store locally, but I doubt it, they are rare. I would contact Midway and the base manufacture and perhaps they will offer a solution. Whatever you do, take it slow, and think it out. You don' t want to make the problem worse.

Good Luck-Good Shooting.......Jim