Lenny shed some light about what all this water might be about:
"Entering water acts like a sensory deprivation chamber and this helps in the dream like state. Sensory deprivation chamber takes away your senses. smell, touch, etc. It is also known as "isolation tank" which is used neuro-psychiatrist (if all stimuli is cut off to the brain then the brain would go to sleep).
The tank uses special salt to adjust density and the water is at skin temperature.
The ears are submerged in the water = reduced hearing. Arms float to the side = reduced skin sensation and body feeling since air and water are at the same temperature as the skin. Water does not contain Cl = reduced sense of smell.
The tub of water is how Leo enters or exits the dream world. That's why we see him being put down into the tub filled with water."
I buy it. In fact, the only reason I didn't say it before was because it seemed like something out of the script leak. Now the only question is: where does that put the tubes? Are they an alternative way into the Mind-Cities? Are the water tanks/tubs and tubes all part of one system?
This train of thought makes me think that there has to be a Host Mind for which the city to exist and then others can travel into it. But then it gets tricky. If that is the case, the logical assumption is that the Host Mind can use his/her Ideas to "transform the world" whilst a person is in it, hence the danger.
But then why does Leo say, "Never recreate from your memory! Always imagine new places." Note, this is not pure voiceover in the trailer; Leo is actually telling Ellen this in Paris, while in the Mind-City. How can we tell? Because of the Paris city-folding scene.
So that means Visitors such as Leo and Ellen in that scene can affect the Mind-City with their Ideas, even while in it. What do you think?
Giving further evidence for a previous theory, Aaron Faulkner called the water glass scene from teaser 2 back to my attention.
Look at the bottom left part of the water glass.
You can spot the reflection of a lamp, with light from outside blowing out the frame around it. Yes, I know what you're thinking. "He's finally gone crazy." Well, yes, but also watch the reflection as the scene goes on.
As the angle of the water becomes more extreme and agitated, watch the lamp reflection.
You can see a shadow taking the place of all the light earlier from outside, all of this occurring while the water's angle changes. As if the vibrations weren't enough, I feel that this is strong evidence that at this moment, the Mind-City is shifting, hence the movement from light to shadow outside, kind of like the shadows the Mind-City casts during the Paris folding sequence:
Aaron also cited someone's idea that Inception is about memetics. Memes.
"In his book, Dawkins contended that the meme is a unit of information residing in the brain and is the mutating replicator in human cultural evolution. It is a pattern that can influence its surroundings – that is, it has causal agency – and can propagate." Wikipedia said it, it must be true.
By that definition, an idea could be a meme. Considering how the tube seems like a surgical method and Leo's wording that an idea is a "parasite," I think this scientific classification of an idea suits the film.
Next up, locations.
So Nolan shot at a variety of locations for this film, from Los Angeles to Tokyo to... you get the idea. While he could have just liked a bunch of various locations from different countries and they'll all be stitched into only a few locales in the final film, I think the characters will actually go to all of these places in Inception. The only question is whether they'll physically be there or whether some of these places will be Mind-Cities. Just something to think about.
Now as for the trailers, let's place where the characters are:
Leo seems to be in some sort of bathhouse, judging by the circular sink, or a dilapidated warehouse/building from the general surroundings.
That window seems to match the vibe of yet another place in the trailer.
Is Lukas giving Leo the Kick in the same place?
And is Cillian and the other man being held prisoner here too? Also: