The left shoe trick - throwing my shoe in the car next to the kid - probably saved my kid's life more than once.
One kind of parents who have these tragedies are tired ones. Which is most parents with small children.
Edit: not relevant in this case, but I'll take any chance to advertise the shoe trick.
I felt the same, until I had my first lousy sleeper (child who had trouble sleeping due to minor health stuff). After a month of lost sleep, I couldn't remember my own name sometimes. I read once that sleep deprivation is effectively brain damage, and after that experience, I believe it.