Each pet class player must dismiss pet before he jumps down. If you complain abut that, you are just noob who don't understand mechanics of game.
You can post at suggestion forums for Blizzard to add special skill for that classes "grab you pets to pockets while I jump down button / skill" but I'm 100% sure ppl will still forget about that and pull whole instance.
Most hilarious pull are done this way in Gnomeregan it's like 500 mobs incoming in amazing weave