in all honestly, use the nub
my metro I just picked up has the same problem. I tried for 2 hours to get the broken off part. I used a lock-pick rake, a magnet, a destist's pick, sewing needles, small screwdrivers... If you really want, the lock cylinder will come out of the column. A Hayne's manual will explain the procedure for this. But it'll run fine without taking it out.