Contrary to popular belief, gladiators weren't actually slaves fighting for their freedom. They were trained warriors competing in sport for entertainment, more like today's athletes. Also, gladiators didn't fight to the death. Usually it was to first blood, or when one conceded. You wouldn't put the money & time & training into a gladiator just to have him killed. He's an investment. However, slaves, POWs & traitors of the state were often publicly executed for entertainment. Animals like lions & tigers were kept underfed & malnurished underneath the Colloseum floor for gladiators to also fight.

I'd imagine being a gladiator was more like a job, fighting for money, fame, and entertainment. A little diff from the movies