If a character is waiting on a GM to continue a quest (which is fine), he/she doesn't need to necessarily be stuck there. I'm just making it official since there wasn't really mention of it before, but if you do this you are free to leave whenever, but when you return to the quest (or quest battle) your stats should revert to what they were previously.
So if you are in the middle of a battle and have 500 HP left and 1000 EP and decide to leave, you regenerate like normal, however when you return your stats will revert back to what they were before you left.
Just clearing it up.