[Rawknees'Turbo]

It looks like there is plenty of room to do the repair while leaving the arm installed.

If it were me, before drilling it out outright, I would attempt to use an "Easy Out" (largest size that would be reasonable) and drill the appropriately sized pilot hole using a left hand drill bit. The counter clockwise cutting motion of a bit like that tends to loosen the broken part, along with the heat generated, so that an Easy Out works with little effort. Also, use lots of a quality penetrating oil, such as Kroil.