That bolt is kind of important. In Drumsy's case, it shouldn't be too hard to find a rental place with a right-angle drill to insert the proper sized e-z out to remove the broken stud.

I had a Jeep that poured smoke out of the manifold area when a manifold bolt completely backed out. 'Had something to do with galleys in the manifold or head allowing coolant or oil to hit the manifold. Nice way to simulate engine fire.
good luck,
-W-