Looking at the footage again, Boonen drifted back while he was having some pommes frits and a duvel, thinking I am the strongest one in the group, also probably thinking of equalling RDV's record, but also lamenting I am knackered from doing so much work. Cancellara accelerates to cover a Roelandts? squirt off the front, Boonen gets baulked by the 2 HTC guys, Flecha et al watch Cancellara stroll past. Cancellara looks back once, twice, and I'm off! Just another opportunistic jump off the front to test the other guys legs.
Cancellara little burst off the front was good for a 20-30sec break (you will have to look on the Clinic thread for the reason for the other 2 minutes). But then everybody pulled the pin, except Boonen who always looked like he wanted to win he just did too much work leading up to Cancellara taking off - and afterwards. That is just the old story of bike racing - if you want it do the work, and then we will benefit when you are cactus - ala Hushovd and Flecha.
Enhanced most probably, but still a phenomenal ride, given the immediate opposition.