I was once in my parents' house when somebody (probably my sister) left a gas stove on, unlit. I was in a spare bedroom on the opposite end of the house messing around on the computer. I thought the headache I had was just from eyestrain, from looking at the monitor too long. But then, my mother walked in and just about freaked. She smelled the gas right away, but it had somehow impaired my judgement and I never recognized the tracer scents they put in (mercaptan, sulfide) so you can smell it. We opened all the doors and windows and vented it out, but holy shit, one little spark and it would have been KABOOM. (A few years later, that house was destroyed by a hurricane.)
Soph, why would your brother draw a picture like that? Sibling rivalry, I presume?