It forces Jim out of his comfort zone of ironic detachment and into a position of genuine anxiety.
Jim’s quick thinking—claiming he had a crush on her "years ago"—is a heartbreaking moment of self-preservation. [S1E12] The Secret
It marks the beginning of the end for Jim’s ability to hide his feelings, leading directly to the events of "Casino Night." To help you dive deeper into this episode, It forces Jim out of his comfort zone