So, in E7(S). You'll get a debuff.
The Debuff has arrows. Left, Right, Up, Down.
Those arrows are relevant to where YOUR CHARACTER is facing.

For example, if you have the << debuff and you're facing the boss north. You'll end up teleporting to the left.
Same applies if you have the front, back, and right debuffs.

If you use a skill you'll reset and face the boss (not always true north but we can always think of it that way) thus causing your arrow to be misaligned.
There's a timer on the debuff, around 4-5 seconds left you'll want to stop DPSing or Healing, unless doing so won't affect your teleportation location. Then you teleport, live and move on with your life

If you're Legacy it helps to rotate your camera to manipulate it. And there you have it. E7(S) teleports made EZPZ by yours truly, Niu Wang.