Lassiter’s Reaction to Shawn’s Goodbye Message

I just finished watching psych for the first time!! It was so great and I think it’s my new favorite show!! I still need to watch the movies though. But something that was on my mind is Lassiter’s reaction to Shawn’s message. He stops it before Shawn reveals the truth to him. His reaction confused me a little bit. I didn’t really know what it meant. Is it that he finally got what he wanted from Shawn? I’d love to hear some thoughts.