I'm sorry to sound cruel but I would hope at 8 years old after escaping the house and going to the meeting place, if he were for some reason, unable to find either of you there after not so long a time, would head to a neighbors instead of freezing to death in the back yard. Chances are if your actually human, you or your wife will forsake your own safety to make sure he has made it out safe by going to his room. Being he is human he would most likely do the same, going to your room. On another note, why are you meeting in the back yard? Why not meet in the drive way where a first responders will arrive at and be able to offer immediate assistance. And a first responder could be a neighbor or passerby, so don't say he'd freeze to death before help arrives.