Lily's face softened a little. Severus was calling her his best friend again. And he was angry again. She felt a little bad for having made him angry again, but she felt as if she needed to beat it into his head that he wasn't going to hurt her and that burying himself under a rock wasn't going to make the fears go away.
"Because that way, when you open your eyes, you'll be able to see that I'm just fine." She offered him a small, soft smile before continuing. "Because I'm a big girl and I can take care of myself, even from you. Because I trust you and I know you aren't going to hurt me. And finally, Severus, because hiding yourself away somewhere is not facing your fear. It's giving in to them."
She wanted to reach out and put a hand on his shoulder or pull him into a hug or something, but considering his mood, perhaps that wouldn't be the best move. Trying to decide when physical contact was and wasn't okay between them was still tricky to Lily.
"I'd be a rotten friend if I let you do this alone, Severus."