"We can worry about that once we've figured out what to do about them."

Helen's concern is protection, certainly, but she's more worried about what to do with them once they arrive. How to deal with even one is a start, the stepping stone they'll need before they deal with numbers. For now, she's content to work from the ground up, as normal, and she isn't very worried. A little concerned, yes, but not afraid. They've dealt with a lot of crazy things in her lifetime. They can deal with this as well.