[Hogosha]

If you can get the screw into the "almost" position with a magnet from the outside, maybe you could grab it with a peice of flexible plastic rod with a lump of sticky wax on the end. Something the consistency of "Magicians Wax". If you can put enough pressure onto the screw it may grab the threads enough to pull out. If a small pea size peice of wax falls into the engine, it should just melt away and do no damage.