May I respectfully suggest here's a few ideas:
1. Drill it out. Use a 5/16" or 3/8" drill to remove the head material from the reamining bolt shank. This will free the hinge and then you can pound out the shank or drill and re-thread it.
2. Cold Chisle it out: Using the cold chisle cut down from the outside of the Torex head into the center, of course not cutting into the hinge. Repeat this 4 time so you have a "cross" chisled into the head. Using a the chisle lift up on one quarter of the material that's left and pound it toward the center of the bolt shank. Once it's toward the center, pound it back. Just work it back and forth untill it fractures. Repeat the process with the ohter quarter pieces.
3. The weld method. This is a long shot for me, but has worked.... Grind a taper onto a 5/16" bolt that will fit into the existing hole you've drilled. Using an Arc welder, weld that little bolt to the existing Torex and to the material that's left. Let it cool about 2 hours... and go back an see if you can turn out the bolt and the remains of the tool and Torex material.
4. Use a torch to heat up the bolt and then walk a way an let it cool, much the same as above... but it toasts the paint.
5. Use a GOOD LIFETIME WARANTEE Torx socket and impact gun. Sometime if it ain't rusted enough one can break it free.
An air operated cutoff tool, chisle, and impact hammer is nice for this job, however a drill mounted cutoff blade is adaquate to get the job done.