Take a hammer and mark the center of the bolt with a punch
Drill a hole in the center
Use an extractor to remove the bolt:
With the 14mm bolts that are on the cranks. I really doubt that extractor will be able to remove it.
OP: We've removed cranks at the shop where the crank didn't need to be saved - 1 minute with an angle grinder on an AL crank is all that is needed to remove it.