Even if I hadn't been absolutely positive that the movie would be great after hearing only the premise/seeing the teaser, I'd still have seen it solely on principle because of Joseph Gordon-Levitt. That's a double whammy!
My guess would be that the actual depth of the protodermis, while possibly quite deep, is irrelevant in your situation. You're probably not going to make it out very well.
Recently Finished The Corrections by Jonathan Franzen, and am now reading Sogyal Rinpoche's The Tibetan Book of Living and Dying. Both very good reads.