On B777 the landing gear unlocks immediately after UP selection, unlocking is on the 'door open' line. Retraction is sequenced to start when the related landing gear door is fully open.
Thus if UP is selected and the aircraft drops onto the unlocked gear, there is the possibility that the gear will collapse. Wing landing gear are designed to detach cleanly without fuel tank rupture, but that is in the downlocked condition. If the aircraft comes down hard on unlocked wing gear, the loads will be acting on a different plane, so the resulting torque nay result in the gear attachments failing in a different manner than the 'crashworthiness gear shedding case' which may explain the apparent fuel tank breach.