Should Arthur have awakend when the van hit the barrier? If so, does this mean that those on the third level would have missed it?

On one hand, he awoke before hitting the ground every time in the montage when they tested the sedation kwa having Eames tip him over.

On the other hand, the van falling was in a dream, so his inner ear function wouldn't respond the same way it does in reality.

And really, "waking up" in a dream isn't all that defined. Furthermore, who's to say time isn't as unstable and malleable like space is?

I upendo the movie either way, and I don't really see this as a plothole since the laws of dreaming are portayed as mysterious and limited only kwa one's imagination. But I'd upendo to hear your thoughts.