Kiserlovski stopped cause of a puncture suffered by his team leader and they were both standing by the road attending to their bikes, when Leipheimer crashed into him at full speed, ended up with a broken collarbone. He definitely knew, maybe not the first time he jumped, but by the time he went for the second time there was no way he didn't know. He did seem to slow down eventually, because the main group seemed to catch up with him out of nowhere, as he was already 2 minutes clear of the Wiggins group. Probably slowed down to save face. There's a reason him and the rest of Europcar riders aren't very popular in the peloton.