During (S)Cascade, Dave and Rose take out the Tumor, which houses two tubes, one red and the other blue. Is there a reason there were two tube-things?

The red tube contained the human’s universe and the blue tube contained the troll’s universe. The human’s universe was destroyed once Bec Noir sent the Red Miles into the Genesis Frog and the troll’s universe ended when Spades Slick shot Snowman. These two dying universes fueled the bomb and created the Green Sun.