If there is still a lip above the block, I think I'd try collapsing the sidewall by using a screw driver or a dull punch and tap the edge towards the center. If you can get the lip to begin to fold in, you can work your way down into the hole. If you get the tube sidewall to collapse towards the center on the full length of the broken tube, you can probably pull the tube out with a needle nose pliers. Worth a try before you bring out the drill. Gene