I don't understand when people refi and "get their money back"

[Scott L.]

Please excuse my ignorance in this post, but I listen to podcast after podcast on my drive to work.

This morning I was listening to Bigger Pockets Podcast 210, about a younger couple starting out, purchased their first property a 4 plex and are house hacking.

The purchased it for like 400K, but down 45K and were cash flowing like 1K a month.

This is my question:  The guy on there said they then refinanced the mortgage 10 months after they bought the property and took out 50K, basically getting everything back that they put in it.  

I don't understand. People say that on the podcast none stop and I think its the theory around BRRR? But I don't get it? Aren't you then paying another loan on the amount you "take back out."

And if you use that money on something else isn't that just money you are paying an additional fee for?  I'm really confused about how all these people "get their money back out"