At a moment of weakness, Bruno denies knowing Shmuel and does not stand up for him. It is at the moment where Bruno showed compassion and care by ensuring that his friend had something to eat. Yet, the moment is interrupted by Kotler's presence. In this instant, Bruno recognizes that his transcendent friendship with Shmuel can be contingent on circumstances. Showing fear of what Bruno knows is possible, he denies knowing Shmuel. It is significant for a couple of reasons. The first is that it shows how dreadful conditions are at the time. Bruno is a good friend and one who does care for Shmuel. Yet, the awareness of what is happening and the conditions that surround them reveal themselves in this instant of abandonment. Additionally, it is significant because it proves to be an epiphany for Bruno. He understands that he should never turn his back on his friend. While he did so in this instant, it is a moment that serves as a reminder to never do so again. This will prove to be prophetic later on in the narrative, when the stakes are so high and traumatic. One singular moment of callousness becomes something never to be repeated again, to both of their detriment.
The fear that Bruno has of Kolter is visible throughout the stroy. Even though he tries to act strong from within, he is unable to be assertive in front of the soldier. Bruno had been told by many people that the fence was "out of bounds at all times" zone and meeting Shmuel is not allowed. It is also noted in the chapter that Kolter considers himself the head of the house when Father isn't here. So he was scared that the truth might result in him being in major trouble. All these reasons combined cause Bruno to deny his friendship.