Apart from the awesome characters, what I liked best is the detailed foliage outside the windows! You've created layers of depth and drama in a single scene!
Even if the men weren't present in the scene, just the extraordinary textures and lighting on the arena walls, pillars, windows and foliage is awesome.
But adding those guys is like an icing on cake -- a masterpiece in serene beauty suddenly becomes a masterpiece in dramatic detail! I notice you just used 4 primary color hues (predominantly green, and white, brown, and yellow), with perfect shadows and highlights everywhere!
The attention to detail, right from the characters' pose, anatomy, clothing and weapons, and the dramatic tension created in this scene, is just extraordinary!
The old guy is going to dodge the jumping guy, grab his sword, stab him, then he dispatches the archers, picks up an arrow and a bow, shoot the guy with the spear. Runs up to the three swords guys and kick some ASS!
The old guy stuns the pouncing guy with a jab to his neck; uses him as a shield to absorb the swift arrows from the archers; blinds the spearman and archers with scooped dirt and pulls the spear before they can react; somersaults up the ramps and kills the archers with the dead man's sword; kills the ambush leader with a well-aimed throw of the spear ; and then finally takes on the swordsmen and unarmed spearman; or he jumps down back to the center of the arena; dragging the shield-corpse to the narrow doorway, and armed with the sword, he can finish off his pursuers in single combat in the narrow confines of that dark tunnel.
My jaw dropped, seriously. Words fail me to describe how amazed I am by your work! The composition is flawless, the sense of captured motion and emotion, the dramatic lighting, the ambient colours... Wow!! I am floored.