Well, your precautions have proven adequate so far. Most of the hazard belongs to people who are trapped, foolish or brave. Try to think of all the sound defences you have, and how some risk is not only unavoidable, but a normal part of feeling alive.
A feeling of security is amazingly quirky. I was once working on a total house renovation, and when it was almost done, I was told to check all the windows and doors for adequate locks. I did a tour, made a list of what was missing, went to the hardware store, and installed the lot. I handed over the new keys, and was just standing outside, thinking about how secure I had made everything when the last person left and realized that they had locked the keys inside. With my new mind-set, I realized instantly that the basement was still vulnerable. The next day, the house was actually secure, and the keys were installed on two key-rings.