Yes you're right. It basically saves the battle at the point your last toon died or the battle timed out. It's not just turn meter that is effected but their cooldowns as well. As CCyrilS has said, sometimes it's better to retreat if you just got completely overmatched. Sometimes it's good to just let the battle end if you know they've used up their ability cooldowns and the next match could go easier because of it. With really tough teams, people sometimes bring in a squad to make the opponent use up their cooldowns and then just let the timer reach 0.