Need help! Rocker shaft bolt broke in head. Need removal advice

The tool manufactures make left hand drill bits. If you can get
your hands on one, you could try it. A lot of times they will
hook in the bolt and turn it right out. I got a set from Snap On
and it came with the easy outs. Good luck. Cover everything up
well and keep a vacumn close to pic up the metal. Hope you don't
have to pull the head.