Gracefull handle known errors

How can I handle certain errors in a way where I just pop up some sort of message and close the game gracefully so it gets back into the editor. For example - right now I have certain requirements - to have one and only one “camera pawn” by the time game starts, and a few other sanity checks like that. I read Rama’s posts on UE_LOG but if I use Fatal type on that, that will throw an exception and I’ll have to close the debugged project, resulting in having to start again and wait through initialization, etc. Instead , I’d just like to be able to show the message , gracefully exit the game and go back to the editor.

Any ideas ?