After Brock recovers , Jesse says that the boy had likely been poisoned by accidentally eating Lily of the Valley berries .
Gus was not responsible ; Walt responds that killing Gus was still the right thing to do .
After Brock recovers , Jesse says that the boy had likely been poisoned by accidentally eating Lily of the Valley berries , and Gus was not responsible ; Walt responds that killing Gus was still the right thing to do .