Are you allowed to remain alone in the cockpit if the other guy goes to the toilet?
My point is: especially at high altitudes, leaving someone alone in the cockpit behind a locked door doesn't seem a good idea to me.
Yes we have cameras, but... in case of decompression...
And what about the risk of a suicide attempt of the only guy who could lock everyone else outside? Not so remote. It has happened before, at least 3 times....
I personally have a FA come inside when one of us two goes to make a phone call to the pope, but I'm amazed it's not mandatory here...
