@Nanobody, Thats interesting take that you think the vehicle was still running. I got the sense the vehicle was off but left in gear and the lights were on. But, if the vehicle were kept running (not sure why anyone would do this) then you are right that the lights would remain on until gas ran out. But if the vehicle weren't running, then I would think that the battery might have drained over the timeframe involved. I'm now confused by this... going back to read the AW again.
With your theory, someone would have had to stopped the vehicle, left it in Reverse gear with the lights on and exited the vehicle and abandoned it. Is this what you think happened? If so, why do this?