Like we all know, Heller said that something in the ending of S06E01 was important.
People have argued about whether it is the 666, pigeons or the smiley face.

How about what Partridge says?
Or actually not what he says, but who he says it to!

If Tyger Tyger is the password of a secret organization, choosing those words as your last seems rather stupid if the person you're talking to isn't involved in the organization (of course it can be simple mumbling, but why would Heller choose those words for that?)

Now, what's interesting is that Lisbon actually seems to react to the words, and she's clearly confused and thinking about what to do next. She can of course be confused for several reasons, but it looks to me that she's taken aback by learning that Partridge is in the organization. It's like he knows she's in it, while she doesn't know he is. And it's like he wants her to do something (something a member of the organization would do for another member), maybe clean the place up? Or inform someone else what's going on? Or play along with what's about to happen (taken by Rj)?

I'm aware this theory is long from complete, but I think Lisbon is somehow involved in the Tyger Tyger organization, whether it's connected to Red John or not.

Watch this if you don't remember the scene:
http://www.youtube.com/watch?v=w4mhDdZPD-o