Massive plot hole

So we know the sensation of falling in real life wakes you up from a dream.

We also know that the new sedative that they make for the main mission has been specially formulated so that the inner ear function is not affected. They even prove this by showing JGL's character being jolted awake several times.

They then use the falling mechanism to kick them out of each dream layer. Here's the problem - the inner ear will not help them in the dream world, only the real world.

You can Google how the inner ear works but its basically how we balance ourselves and its physical. So makes sense that it could be used to trigger a wake up call.

However, in a dream there is no movement of the head and therefore no way of manipulating the inner ear. In a dream you could fall for a million miles or ride a thousand rollercoasters - it wont affect your physical senses because dreams are not real.