I decided to pick up the "What a Rush" Talent for my Rogue. That Talent grants you bonus maximum and turn AP if your health is under 30%. So I had Edward stand in poison for a little bit.
The bonus is a whopping +2 to Maximum and Turn AP. You get that and more from the Rank 1 Fire Elementalist skill Wildfire, which can be used at any time and doesn't have the condition of "anything breathes on you and you die".
Now maybe that +2 AP really makes a big difference, and I will try it out for a while, and it is true that it's making use of something which will happen anyway, but I kinda don't think it will end up being that great a use of a rare Talent point. If it was +4 Maximum/Turn AP, then that sounds more appealing.