The W212 with Drive Select (i.e. the transmission selector on the steering column) automatically engages Park if you open the driver's door when stationery.
This means that you can stop while in Drive, use brake hold and take your foot off the brake pedal, and then if the driver's door is opened the transmission slips into Park and you remain stationery. However, for reasons best understood by the men in Stuttgart, if you stop while in Drive, use brake hold and take your foot off the brake pedal and then the passenger opens
their door, brake hold is disengaged and the transmission remains in Drive.
Don't ask me how I know...