See also:

Automatic locking feature
The vehicle locks automatically when the ignition is switched on and the wheels of the vehicle are turning at a speed of more than 9 mph (15 km/h). You could therefore be locked out when: - ...

Cleaning the headliner and carpets
  Headliner: use a soft brush or a cleaning agent recommended and approved by Mercedes-Benz to remove heavy soiling.   Carpets: use the carpet and textile cleaning agents recommended ...

Important safety notes
WARNING Make sure the tailgate is closed when the engine is running and while driving. Among other dangers, deadly carbon monoxide (CO) gases may enter vehicle interior resulting in unconsci ...