Got it out! As suggested, I used a center punch against the exposed edge of the flute to counter-rotate the bit. It was still a little too tight to slide out, so I used a diamond-tip dremel cutter to grind a small indent on the OD, where I seated the punch to tap the bit backwards until it was loose. Had to grind a new indent a couple times, but eventually it was loose enough to slide out the rest of the way.
Once that was done, I finished drilling out the oil passage with a new drill bit. Mama didn't raise no quitter... and I didn't want to leave any rough edges in there. Of course, this time I did it much more carefully. The whole reason the last one broke is because I got impatient and careless on the last hole.
Next up is cam bearing installation, then I'll start putting everything back together. Ideally, this thing will be running next week.