I got power word killed while a mob was engaged. It happened inbetween rounds.

Or at the very least a description of who/what/where?

I was there with him, but I don't have a log. He was tanking with an archon behind him. I was resting in the room with my archangel fighting the death knight. He fled but me and my archangel stayed. He came back in between the end of the round he fled, and the start of the next round when the archangel would land his next hit, and got PWKed.

Klaak

Great spirits have always met violent opposition from mediocre minds.
-Einstein

There is a check on that prog to see if the mob is fighting. If you flee on the tick and walk back in before the mob has a chance to re-engage anything it will still fire.

This is the exact same problem where mobs track out of a fight when the tank flees right on the tick.

Without completely re-writing how combat works this isn't going to change.