Exercising options really isn't a good thing (or a bad thing). If he exercised the options, there's probably a holding period (like 30 days or so) before he can sell, which means there is a belief the share price is stable. However, there's also a fear the price may have peaked as well, thus "strike while the iron is hot". It's really a neutral move, probably based on a personal need more than anything.
Regardless, PRB will continue to go up. Spacemonkey is just playing with your gourds - just ignore him/her. Seems whenever space says something, the stock eventually moves the other way. Just the puppetmaster trying to pull your strings.