there is no problem with open doors on a car when its jacked or on a hoist . chassis are not designed with doors as a load bearing item although difficulty opening and closing them while the car is lifted may happen as soon as the car is on the ground all is well. i am a auto technition by trade and went to school for chassis fabrication . note that on badly rusted vehicles the doors may have become load bearing , but at that point finding another car would be in your best intrest.