He doesn't seem to have much introspection on the fact that he's been killing hundreds, if not thousands of people playing this game. In the beginning he even says he uses a tactic of purposely sending weak parties, who will get decimated, in order to scout strong floors or learn boss patterns; they would have all been living people he just callously sent to their death.
And he's just one of the thousands to millions of people playing the game; it's a genocide factory meat-grinder of a mind boggling scale.