In facebook php sdk 4, apps will work outside facebook?

I used the example shown here to create an app with the new facebook sdk http://ift.tt/1nvSQgr

After login, the app redirects to my domain and entirely leaves facebook. Is that okay to be done? Because here it says "Don’t build an app whose primary purpose is to redirect people off of Facebook." http://ift.tt/KHzX9P

Is there a way to do the login with the app and stay in facebook?

I tried changing the code below and instead of my domain, I put the url of the facebook tab in which I have the app, but that creates a loop, because login can't take place.

$helper = new FacebookRedirectLoginHelper(REDIRECT_URI);

I guess it's because it needs to access the php files of the sdk on my app's server.