Non-Verbal Communication" Star Trek TNG

Every time I watch this episode, I watch the look that Picard gives Riker.  It is one of my favorite Picard moments.  Picard generally out-thinks his enemies like this all the time.  Plus, I love the F’me eyes Crusher gives Picard at the end.  Did she know that he was replaced by a counterpart?  Was she just messing with Picard?  I also find it interesting that she sits in Troi’s chair.