Kairos thought of many things, but found himself to be quite limited in stalling. After all, his spells were oriented to combat, and attacking Chen and Bob would be hard to excuse despite there being a monster there to hit.
He didn't want the monsters to die just yet, but didn't want to make that clear.
After thinking within a split second, he found his only real option was convincing Chen to avoid attacking the monster.
"You have to save Bob!"
Chen had his knives pulled back, ready to stab the monster, but hesitated upon hearing that. In the end, when he saw the monster's claws going for Bob once more, he relented and picked him up, fleeing the moment he could.
As for the monster, it did not try to chase. Instead, it continued to run away, but didn't forget to cast its spell once more.