How the teacher reacts when something goes wrong tells the class what’s important.
Bruce is a dance teacher par excellence and originally said this in the context of teaching Scottish and English folk dancing. It also applies to any sort of teacher / student interaction, and any interaction where someone has power or influence over someone else. Let’s paraphrase the quote:
How the manager reacts when something goes wrong tells the team what’s important.
How the senior developer reacts when something goes wrong tells the junior developers what’s important.
I have had the misfortune to work on several teams where one person (usually, but not always, the manager) had to have their ego maintained at all costs. If anything went wrong it was not their fault, and any attempt to get them to take responsibility was doomed to (very unpleasant) failure. It was very clear what was most important – their ego. Because of that, entry #2 on the importance scale was for the rest of the team to protect themselves from the egoist. If we were lucky, entry #3 might involve producing a quality product.