Guild Wars 2

Over the last few weeks I have been able to enter into the red circle that denotes the position of an enemy hostile. Upon entering, I find I am able to do an increased amount of damage, and I am able to avoid damage easily. Is a player supposed to enter the red circle?
Example is the broodmother on the north shore of Frostgorge Sound. I can get inside of her red ring by jumping and turning in midair. Once inside, I avoid all of her breath attack, and I seem to do twice as much damage to her.

Anybody ever notice this?

Depends on the skill. You can just walk in if you have melee assist disabled, no need for any jumping.