Claudinei Angelo was going to lose, and he knew it.
The Brazilian MMA fighter was getting overpowered by Evilasio Silva in a recent fight in Juiz de Fora, Brazil. And when Angelo tried to quit, the referee refused to end the fight. At that point, Angelo knew he needed to get creative to end the bout on his own terms.
Angelo attempted to open the door to the cage, but it was locked. So instead he climbed over the cage and simply walked out of the arena.
Interesting tactic here. It's hard to fault Angelo for not wanting to take a beating here, but on the other hand he is an MMA fighter, so that's part of his job description.