I think the $300 was a big thing for NC as she may have been planning on using it as a down payment on a rental until her family could transfer the funds she needed to move out.
I don't think NC would have told anyone her plans about moving until everything was a "go". From the urgency of her phone call she may have been fearing exactly what happened to her if he found out before her move actually happened. Her friends have demonstrated they would drop everything to help her (when she was moving.) When I left my husband no one knew, even my father. The only people I told was my friends who were helping me and I didn't tell them until I had a place to go and was 100% sure of my plans. If I had 2 small children to consider this would have been all the more important to me. If she found a furnished place the only things she would have needed to take would have been clothing, bedding, personal items, and the girls' toys.