It means that they've come to realize something... that they rely on each other... and as they realize that they say "Uh-huh."
Ūađ ūũđir ađ ūau hafa gert sér grein fyrir ađ ūau reiđa sig á hvort annađ, og ūegar ūau gera ūađ, segja ūau... uh-huh