Good idea. Explosively eject a massive burning battery pack into the path of the unsuspecting traditional combustible car behind you and watch it burn in your rear-view mirror as you coast away on the backup emergency battery...
Which would increase the safety statistics of the model s over dinosaur burning vehicles, too!
Not sure how the car would know it was safe to drop the battery pack; you wouldn't want to drop it in the middle of an Interstate. Even moving the car away (can that happen w/o a battery pack?) how would it know which way to move safely without getting into traffic, hitting guard rails, emergency vehicles, etc.?
It looks like he had minutes in this case, so driving to the side of the road, then confirming dumping core, driving forward 10 meters, and shutting down, seems viable. You could presumably keep enough energy for this in ultra caps or a separate unaffected part of the pack, or do it with inertia.