As everyone seems to be discussing how RJ knows about PJ's memories, specifically his happy memory of that girl from his childhood, may I offer a theory?
Kirkland has been following PJ's movements since the beginning and was aware that PJ was in a mental institution prior to entering the CBI. As he seems to be able to access any information he wishes, isn't it possible that pycho-analysis sessions at the insitutition could hold record of PJ's past including memories and inner-most thoughts? This information could then be readily passed along to RJ.
I believe that Kirkland is, at minimum, an associate of RJ, but I feel his on-screen actions make him "too-likely" to be RJ himself.
As for the wrist-brace on Lisbon:
IMO, she made some attempt (to be shown perhaps next season) to get into PJ's room to see his progress. I feel she truly loves PJ but does not yet fully trust him. I think PJ noticed the potential break-in, hence his expression when she says she tripped.
