Things that feel the riskiest probably aren't, like abseiling. It's probably more dangerous to drive around the M25. You don't think about it anymore. It doesn't seem so dangerous. Thus home was usually spontaneously perceived as the safest environment because it is known and you are surrounded by people who you know care for you and will protect you.
Home is safe.
Your parents are there. At home there's always a chance something will happen. Electrical things or smoking in bed. But you don't think about them as it's all so normal. It takes some kind of incident to shake off this complacency.