I was going to say exactly what you said about dreams.

I don't remember his name, but a psychologist studying dreams realized that dreams were happening in split seconds, when he dreamed that a book had fallen off the shelf and hit him in the head. He perceived his dream lasting several minutes. But he was actually woken up by a book falling on his head.

In the split second between asleep and awake, when the book struck him, he had an entire dream.