She has Harry in her arms even as she hears the footsteps on the stairs, and there’s a part of her that wants to believe it’s James coming up to tell them everything’s alright, that it’s James coming up to hold her tightly and wipe away her tears, but she’s not that naive, and frankly, irony had done enough to the Potters so that optimism wasn’t an option anymore.
She kicked a box towards the closed door in an attempt to build further upon her barricade, but she was panicking, and she couldn’t breathe, and her heart was threatening to jump out of her chest and she clutched Harry tightly to her, kissing his head and trying not to shake.
Time was a standstill as Lily stopped pacing. The footsteps had reached the landing, and she shut her eyes, and she let herself calm down, but it did nothing to relieve the tension in her chest. She put her cheek to her son’s and sobbed quietly as she took the several moments before her inevitable death to tell him she loved him, she would never leave him, she will always stand by him - until the very end.
The door opened and the only thing that allowed for Lily to separate herself from Harry was that in just a few moments - just a sacrifice later - she would be with James, as she should be, and Harry would be safe - living the long life his parents gave for him and knowing that they never once left him. Not once. Not ever. If there was anything she was absolutely sure of, it was that Harry Potter would never be alone.