First off.. I can easily understand how the father didn't see. When you're on the phone.. how often do you look EVERYWHERE. Most people would assume their child will be ok for a minute while on the phone. Some people turn around... From there, he wouldn't have seen.
As for the fitting? I see it. Picture a full sized van. Ok now on one of those side windows? You know how they're huge? well then the bottom of it there are these two little itty bitty windows. I fit through one of those.
I was probably in middle school.. so 6th or 7th grade is my bet. I had help of my sister's NOW Ex-b/f. He locked his keys in, and so he opened that little itty bitty window and turned me sideways and I squiggled my way in there. I fit in that and I was older than 7. I also required help.. but I still got in. Now drop your jaw in awe and worship me!
(like KWSN, King, Tai, Ogre, Z, Etc.... )