I've seen dd pull for tanks and sometimes the tank doesn't pull it off them, let's them die and moves on. If the healer heals this person, well you have a problem then.

When I'm on my tank I generally speed pull, but that's if notice the PT I'm in is full 50s in a low level dungeon. If you have 50s in a low level dungeon, you just know - know they aren't there for the exp. lol That's when I start speeding but if It's like a group of people who are at the same range of the dungeon I'm going to relax and go slow. Clear the whole dungeon for them. They waited hours for it, so may as well give them the exp slow-bro run.

As for being with a PT in a high level dungeon. If your in a duty roulette expert - expect to speed. Most people want poetics and go out the door zoom zoom. lol
If it's anything else, do what you want. Your the tank, you call the shots essentially.