Alternate system works as follows talking about a single wing gear. Quick n nasty version.
Electric motor runs, rotary cam drives cables to unlock the hydraulic lock holding the gear doors closed. (Exactly the same way the doors are opened by maintenance on the ground using the manual gear door handle).
Doors unlock electric motor stops!
Doors fall open, when sufficiently open (proximity switch) motor runs again drives gear lock/unlock hook to release the gear.
Gear falls may or may not hit the skid plate (will on the ground during maintenance as the doors aren't faced with a 150kt airflow) airflow is unpredictable.
System runs full circle and resets itself. (Involves time limits etc complicated)
A failure of a restrictor check valve that slows the initial gear extension or a miss rigged proximity switch may have caused the gear to drop early or fast and hit the door before it was able to get the skid to do its job (the skid actually also forces the doors fully open).
Trying the gear lever could also have stuffed it up as the system would possibly be out of sequence ie the doors cracked open and then an alternate extension was attempted which may have led to the restrictor check valve opening early and the gear dropping fast enough to cause damage and get hooked up.
Looks like the gear door was peeled open from the impact.
Hopefully we'll find out and all learn a bit more about aviation.