Excerpt:
The airline reported, that the captain (64, 16,000 hours total experience) had taken a toilet break and was about to return to the cockpit requiring the first officer (38, 2400 hours total experience) to open the cockpit door.
The switch to open the cockpit door is located about 10 centimeters/ 4 inches away from the rudder trim switch
By mistake the first officer operated the rudder trim switch instead of the door opening switch causing the aircraft to violently roll left and descend by about 6000 feet before the first officer was able to return the aircraft to stable level flight.
The captain subsequently entered the cockpit.
Two cabin crew received minor injuries (flesh wounds), no other injuries occurred. There was no turbulence in the area at the time of the occurrence.