He was alone and he was injured.
That was all the system quest pointed about the leader of the bandit, who was running away from his hideout. Although! he did not have much help from it, the most difficult part of the quest was the location of the enemy. Since the bastard was running away from the camp toward a death zone.
In a simple sense, Kenta could tell that the idiot was trying to die.
Along with that fact, there was also regret that he did not know. How Kenta was already hiding at the place, that he need to cross before reaching that death zone.
Which was why, the moment the bastard would let his guard down. It would be the moment, he will breathe the last breath in this world.