Are you confused by this "Grey's Anatomy" spinoff ad?

It aired during the Oscars broadcast last night, and my wife and mom - who are both avid watchers of Grey's - were so confused... Asking, "How did Warren go from being a doctor to a firefighter?!"

I don't watch the show at all, but I know a good number of firefighters... and, from what I understand, it isn't exactly an easy profession to get into.