I think the fireworks will be more likely due to someone having a bad day than having a good day. ie. If (for whatever reason) Andy Schleck forgets to eat and cracks, I think you'll see Astana/Garmin seizing the opportunity.
There is a minuscule chance that someone will attempt to power over the final climb and take some time back, but as others have said, much more likely is that everyone saves their energy for tomorrow.