When I were a lad, a mate of mine had a big box of fireworks - in the house. He lit one of the small, hand held sparkler thingies - over the big box of fireworks. The sparks fell into the box, and ignited the lot of them.
Exit mate.
Enter Fire Brigade.
They manfully (and completely unnecessarily) chopped down the kitchen door to gain access. They jetted round the kitchen and the living room with several huge hosepipes. They threw a perfectly good dining table and chairs (well, they were only a bit blackened round the edges) out of the window (neglecting to open it first).
Return parents from shopping in town
Still awaiting credible explanation from mate!!