Based on the provided excerpt, the interaction between Helmer and Nora advances the plot in the following way:
Helmer thinks that Nora is afraid his reputation will suffer, heightening the suspense about her real secret.
In this scene, Helmer dismisses Krogstad from his position at the bank by sending a letter through the maid. Nora is anxious and worried about the content of the letter, fearing that it might be related to her secret. Helmer's response and Nora's plea to call the maid back contribute to the suspense surrounding Nora's secret, creating tension and anticipation about the potential consequences.