How to gain access in to bmw x5 2001. battery flat and unable to open drivers door with key

When all else fails - some ideas:

(1) locksmith who does house calls - they'll have a locksmith's kit (consisting of dozens of
oddly-shaped metal wires/probes, wedges, slim-jim, etc.) to open nearly any car door.
This costs about $30-$40.

(2) dealership may be able to help - esp if you have "Roadside Assistance" coverage on your
(new?) BMW.

(3) AAA - you membership may cover accidental lockouts.

(4) if you can get into the trunk with they key - and push forward your fold-down rear seats (if so
equipped), then you're in - but I don't know if this car's seats fold down.

(5) there might be a clever way to pop the hood release from below (jack up the car to see).
If so, hook up a spare charged battery (or battery charger - everyone should have one) to
the car battery just long enough to get in with your key or keyless remote.
Note that you only need to hook up the Positive
battery terminal to the battery - the Negative terminal (of battery charger or battery) can be
connected to any part of the frame/unibody. Why: This car's electrical system uses the frame
as a negative/ground.