See also:

Using the door lock
General information Locking from the outside Do not lock the vehicle from the outside if there are people in it, as the vehicle cannot be unlocked from inside without special knowledge.◄ ...

BMW Assist or ConnectedDrive
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Locking
▷ Press the button. The doors are locked. ▷ Press the lock button of a door. To prevent you from being locked out, the opened driver's door cannot be locked using the lock button. ...