You could see Cav getting across to the Contador group and Froome not quite making it.
What I don't get is that there was one tst rider on the front of the bunch from a while before the split until a while after. A rider who is presumably significantly slower in a time trial than Froome. Froome saw the gap opening in front of him (from the looks of things the rider one or two in front of him let the gap go). He'd been sitting in the bunch - OK so it wasn't as easy as usual due to the wind, but still easier than being on the front. So Cav did a sprint to cross the gap, but did Froome really not have the gas to cross it a little bit slower? Or did he deliberately sit up into the group behind because he'd have been isolated in the front group?
Of course the fallout may well be that the chaps in the front group used a lot more energy today than Froome did, which may well make a difference in a couple of days (dependent of course on what they're using for recovery ).