[Jabbles]

I haven't seen the film since it came out, so I may be mistaken. Didn't Cobb demonstrate to Ariadne that you wake up when you sense yourself falling? By tipping Arthur's chair over as he was dreaming? Arthur (if it was that character) didn't fall on the floor, there was no jolt. Also, doesn't the van land in the water, and no one wakes up?

[natep]

According to the Inception Wiki, we're both right.

> One method used to awaken from a dream within a dream is called a "kick", which is the sensation of falling, hitting water, or a sharp jolt that can startle the sleeper awake.

Although I still think it's terribly inconsistent, if the details matter. There's too many different kicks with too many subtle differences and similarity for me to go into in a reasonable-length post.