As the reset counter for the floor raid hit 0, lots of floor raid requests were instantly placed to the floor administrator, with Karna also sending one.
Usually, when a floor raid opportunity opened up and multiple parties wished to participate in it, the decision of which party got to raid the floor first was left up to the tower's floor administrator, who made the decision based on his own discretion.
As over a dozen applications flooded in, the Floor Administrator of floor 21 immediately rejected the applications of those who did not have a real shot at winning against Perseus, and were only applying out of petty revenge.
This left only three serious applications on his table, with the joint application of Karna alongside the leader of the cowards army being the best of the lot.