If this had been anybody BUT Lassiter, Shawn would have thought there was... flirting? going on. But this was Lassiter. Straight as lines and arrows and everything else in the universe that was the opposite of curved or squiggly.
But Shawn did have to give the detective credit for knowing exactly how to keep Shawn interested. Damn his curiosity, now he just HAD to stay and see what the hell was going on between those cannonball worthy blue eyes.