Lily knew that James was going to die if he stayed. It was a foregone conclusion. She knew, too, that they might both live longer if she fought; her arsenal of curses (don't think about Sev) might buy James entire minutes. They might have a chance - they might be able to hold out until the Order showed up. They'd done it before, more than once, even. Maybe they shouldn't have, maybe it had made them a target - those who have thrice defied him, her mind supplied, a fuzzy memory of Dumbledore's grim voice - but they had done it, they could do it again, live to fight another day ...