There were actually a lot of back-to-back GoH. GoH was doing between 2-700 to the mnk with only one fluctuation of 800, I was in range for one GoH which hit me for about 500, I resisted burn for the only one I got hit by and he resisted 2-3 times. We never resisted para, and his stoneskin went down without any issue at all.
@Toabea: as long as the mage is out of range, neither GoH nor Ululation should be a problem at all. And with only a mnk hitting Cerb, I'd be very surprised if there were any back-to-back GoHs.
Never quite understood how killing an NM like this was only worth 58 exp/limit points. Grats on Cerb, Better luck next time on drops. Algol seemingly proc's triple attack alot more than suggested.