Diesel Bombers - REALLY broken glow plug

Threaded part broke off. Insides pulled out. All that's left is the sleeve. I tried to use a broken glow plug extractor kit to remove the sleeve, but the tool broke inside the sleeve! It's basically a tap that screws into to the sleeve to grab it. Then you use the included puller to pull the sleeve out. But as it was pulling (the glow plug didn't budge), the tap broke inside the sleeve. Before this, I already tried penetrating oil, carb cleaner, heating the head and cooling the glow plug, etc. After this, I've started and run the engine hoping compression would pop it loose. Is there any solution other than pulling the head? I saw a video on the ISI engine where he pushed the sleeve into the cylinder and removed it out the injector hole with a magnet. Is this remotely possible with the PSD?