Not at all being versed in troll body language, but very versed in the art of being given the cold shoulder, Lambert just grins and lets Psi walk away without further comment.

Well, almost. He waits until Psi's a decent distance away -- the perfectly calculated span of steps where the troll's's still within earshot but too far away to turn back and stomp towards the witcher without looking and feeling stupid for deigning to waste his breath -- before he calls out, with a lazy wave:

"Oh, and thanks for the help!"