Poe I think in Arena is supposed to die. But if this taunt works, it exposes some of the enemies. Then with a high offence toon take either the healers or a game changer character like Kylo in the begnning. If you run two healers you can afford one heal for him. One of my friend runs Poe with Luke and Poggle. Poe exposes, poggle buffs offence, Luke does 2x damage to the game changer toon and boom, the game is all yours now.
The problem can sometimes arrise if there is a fast toon in the opposing team.
In GW, after exposing and kill, you can retreat on the second taunt.