Which Thundermarker ?
I was in Susano a few seconds ago and my pet didnt get any damage from then.
Also if you are not standing 50 yalms away from your target your pet is not really stopping attacking, also what is better 2400 mana to get your pet back + swiftcast or moving your pet for 1 second without any big dps loss.
Also there is no reason to pull him away from the boss, stand near the boss and you are fine.
( Tested it right now if you are standing in front of the boss and then go somewhere else, tell your pet to come to you and then again to attack the target and the pet is not stopping attacking.)