That made sense. Concentration improved the worryingly low odds of Severus surviving the battle. Al wanted Severus to survive. Wanted it so much. An alternative outcome was - unthinkable.
Al'd do anything to improve those odds. Anything.
"I'll stay away from the fighting," he said. "I'll do my best to be safe."
They were knotted together on the bed, sheets tossed aside, pillows around them. There was Al's Lumos dimming in the darkness of the room and the two human beings in an attempt to be one for as long as the universe allowed. Al pressed his forehead against Severus's and wrapped his arms around the bony shoulders.
Despite the fundamental nature of any siege to come to an end, Al wanted, against all odds, for this one to continue forever. Even forever was not enough time, not for them, not for this.