D..
I think that this is her way of fighting the end of your sleep routine. She wants you to stay. She will continue to do this until you put your foot down.
I would not act ilke you are worried about her fears. Instead, you tell her that it's time to sleep and that's it. Walk out. When she cries, let her cry. You've got light on in the hallway, the door open, and you're outside of her room. It's not like you are across the street. The only way she is going to stop this is by making her perfectly aware that you won't continue to enable her fighting bedtime like this.
I'd really do this, even though it's hard.
Good luck,
Dawn