I had a small screw on a STTNG lane guide break off flush (or a bit below) the playfield surface. I was able to take a similar size screw, cut off the point from that screw, and then JB Weld that screw to the broken one. Then was able to gently but firmly apply consistent torque to back out the entire piece from the top of the playfield. If this doesn't work for you then you really are no worse off than where you started.