BIL has something similar happen while camping. Only instead of television it was the microwave. Woke about about 3:30 to the smoke alarm going off. The wicrowave was running and bread stored inside was starting to burn. Wife was at home since she had to work the next day, but his young daughters were with him.
Put the fire out, took the microwave out, and literally pitched it out the camper door.
Kids were asleep until the alarm went off, neither was tall enough at the time to reach the microwave, even if they had been awake.
I went through the camper wiring a few days after, found a low voltage problem, possibly caused by partially pinched insulation under the terminals of the breakers, couldn't find any other concerns. He had the camper for a year after with no other issues.