Man, all throughout the game I was wondering about how they knew the fleet was hostile when they hadn't decoded the messages and the first wave of enemies had no weapons. I didn't think you would actually go through with that, though. That is a plot twist well done.
When you use a life spell, it increases both current and max hp. At the end of the buff, only max hp is reduced back to normal levels. This makes life spells significantly better for healing than actual healing spells.