Unlike the movies, gladiator battles weren’t always to the death. Sometimes a referee would step in if a warrior was seriously injured. In rare cases, both gladiators would be spared if they showed extraordinary valiance. The final fate of a defeated, but living gladiator was left up to the crowd and emperor to decided. Unfortunately, most gladiators did not live beyond their mid-20s.
All historic evidence is just stories. So, just because you don't know of it doesn't mean it doesn't exist...