How did the miracle help Betsie and Corrie as they entered Barracks 8?

I suppose that the flees keep the guards away from the barracks,

"to one another and to all. Rejoice always, pray constantly, give thanks in all circumstances; for this is the will of God in Christ Jesus –‘” “That’s it, Corrie! That’s His answer. ‘Give thanks in all circumstances!’ That’s what we can do. We can start right now to thank God for every single thing about this new barracks!”