[forkandwait]

Furthermore, ... I thought it was interesting the movie only went down 4 levels. I have a rule of thumb when working on hierarchical structures (like a directory tree holding lots of data) that three levels of hierarchy is all a person can hold in their head at a time. This is sort of the like the 7 items +/- 2, except I think that the seven items rule only applies "across" a structure. To understand more than three levels deep requires supplementary structures like indexing, sorting, or nesting ...

(of nesting (of nesting (...)))

[waterlesscloud]

When they added the 4th level, I explicitly thought to myself "Oh, this is an effort by the filmmaker to pull us out of logical thought by making it too much to organize in our heads in real time."

[Scriptor]

SPOILERS:

It wasn't too much though, the top two were just sleeping in a plane and a falling van, which isn't too much to remember. The elevator scene was just him setting up charges, much more action was happening at the hospital and the limbo level.