Ok I normally don't buy into the "this is a security issue" bs especially on forums but I think in this case it doesn't serve our collective good to theorize that cabin doors could be opened in flight. That's probably me being paranoid but just doesn't seem like a good idea. An in depth discussion of aircraft systems is better suited for pilots lounges if you really get that bored.... Lets just stick with "you can't open it and why would you want to try"