Cage of Eden volume 17

Yarai is determined to do whatever it takes to save the life of his dear teacher, even if it means taking the life of his friend. But can Yarai actually go through with it? With Yarai and Sengoku facing each other in a battle to the death, it seems like Mami's dreaded vision is actually coming true. However, they may have a bigger problem on their hands, as it appears that the work of uncovering the traps surrounding the mysterious tower may have awoken a new and fearsome beast from its deep slumber.