LOL, I couldn't hold aggro? Seriously?
You ninja charged the boss while the adds targeted you, then denied it. I'm not going to get into a flame match with you at all. Not to mention your memory seems to be a bit flakey at best with your supposed supreme aggro.
Simply put, guards are no comparison to DT's. If you really want to test your supreme tanking skills out get ahold of a TEG DT, and we will see.