Dangerous Mischief at Block 792

We caught this footage on facebook, and can deduce that it was committed at Block 792 by a group of Chinese boys and their intention was to HURT as the conversation between the 2 of them were "released too early". It would be most unfortunate if the ball of fire landed on a person. What is this person thinking about when they commit this act of mischief ?? Once things happen, it wil be too late as fire destroys !!