Not going to weigh in too heavily until there's more info, but at first glance it would appear that this fire did not come from the electric drivetrain. As has been pointed out, the motor is in the midrear and the battery runs the length of the floor from wheel to wheel. If it did start in the front portion of the battery, it just proved Tesla's anti-propagation technology to be pretty fucking amazing since the fire did not spread throughout the pack.
This very well could be a quality or design issue with some other subsystem (my armchair guess? Either 12V system, or contained pack breach), so Tesla isn't off the hook but so I'm not seeing any indictment of EV and if anything an endorsement of the safety of Tesla's battery tech.