Kahn put his hands on the dead body of the floor boss. He felt like patting himself on the shoulders for how tactfully he took out this floor boss.
If not for his extremely well thought planning such as closing all escape routes, removing the option to fly, and then simply scaring down the boss to a state where even he appeared as an immense threat to the monster and simply stood rooted to the spot as Kahn ended its life.
It was no different than the highly intelligent and experienced boss allowing itself to be killed. Kahn thanked the previous floor boss in his head again for giving him such a useful skill. Because even with all of his strength, his small army, and even his Lord-rank subordinates; he really wouldn't have been able to kill the boss so efficiently.