I learned an annoying little thing about MCH and WHM playing as a tank, especially as a pre-40 PLD

Whenever a mob shifts it's enmity to them for even a second, their knee-jerk response is to hit their panic button and use their knockback ability, this is fine if they are far away from me and are facing me so that the mob is knocked close enough to me to pick it up, but most of the time they are relatively close to me and send the mob way beyond my reach.

I'm not going to follow that mob to pick it up and risk having the other mobs attack the other party members.

The best thing you can do is deal with it and let the tank pick it up if you are close enough, a good tank will grab the mob off you before it can get a second or third hit in, or even before it gets the first hit in if the tank is really on to it, but it seems we have MCH and WHM who are afraid of taking a little bit of damage.