Depending on the cg-cp relationship, if the pitch arm is liberated then the blade will either weathervane or else it will go to max plus or minus pitch, whichever is closer. After consulting my ashtray and coffee cup, I'm going to take a stab at guessing what happened. The cg-cp relationship is such that the pitch goes to max + or - (an assumption that the cg is farther from the leading edge than the cp, which may be wrong), and assuming there was some + pitch at the time when the link broke (which is probable since the heli just landed) that blade went to max + pitch, the closest limit, sending that blade up for all it's worth, the other blade down, and into the tail boom.