Ace and Clover used the sewers as an escape route when they got far enough Clover sensed that his Umanda or monster tree had fallen. Clover stopped running and before Umanda was fully destroyed used it to see if the Hakai was chasing them. Once he confirmed that Hakai was still on the school premises, Clover threw some seed into the water, and vines spread through the sewers.
"That monster isn't chasing us we can't stop running for now. I spread my vines here so that I can detect anyone who comes within two kilometers of us."
Once they stopped running Ace sat down his body aching from the hits he took, but that did not bother him as much as the thought of them fleeing from the enemy.
"Damn it! Damn it! How could justice flee from evil?! We should go back and finish the evil monster!"
"And how do you propose to do that? Didn't you see that monster wasn't even serious and we even restricted him so much but it felt like he had room to spare."