Sayis wrote:
This is actually a misconception in groups (and even by hunters themselves). Your pet chasing a fleeing mob will not cause the adds to come.
Very very true. The pet won't be the one doing the aggroing. The fleeing mobs will in most cases link up with the adds no matter how close your pet is. In fact, if you are higher up on the threat list than your pet, you will be the one getting the attentions of the adds.
The solutions posted by several above posters should help you out immensely. As a BM, intimidate is wonderful. It stops the runner, and allows you and your pet to keep smacking the mob without letting him loose again. If intimidate is on CD or you aren't BM specced, Conc Shot is usually enough to finish them off before they link up.
And in instances, you should have plenty of help from the other players to keep the mobs from running. Warlocks? CoR or even CoE works wonders. Paladins? Stun/Hammer. Rogues? Gouge, Kidney Shot, Slowing Poison, Hell.. even Backstab to finish them off. Shamans? That slowing totem and Frostshock. Mages? Various chilling/slowing effects. Poly if you don't mind killing the mob twice (health regen in sheep form). Warriors? Hamstring, Intercept.
There are tons of ways to deal with runners. Calling the pet off won't help.