Why wouldn’t there be a backup? In an old video, the CEO explains that there are 2 more backup controllers on board “just in case ”. Also, considering that the controller is just a dumb interface for controlling a computer I would assume that this computer also has a screen and a keyboard.

My only gripe with this is that the controller has a battery in it, which may cause a fire and smoke but those are well commercialized items made to be used by kids, so I find it unlikely to have design flaws to cause that and would expect to be quite a robust piece of equipment.

I would be very surprised if the incident has anything to do with the controller.