But the thing was that after coming to the second floor you can say those Warriors most likely wanted to find the Boss monster as quickly as they could and because of this they also killed only a small number of those Monsters while they already came to the core area. Naturally even Allen could tell that those people won't be able to find any Boss Monsters because until now they did not kill the required number of monsters that they need to kill to summon the Boss.
As expected when they already came in front of the entrance of the next floor those Warriors also got disappointed as they did not see any Boss Monsters. Not only that you can also see those Warriors discussing among each other that most likely the Boss monster that he faced in the first floor was just a coincidence.