Yeah, even with the water setting Gladiator is stronger, much faster, and more durable, and he doesn't need to breath down there. He can withstand the vacuum of space pretty much indefinitely and he flies through planets and stars so the cold and pressure of even the ocean depths would be like a light breeze to him. Plus he has the eye beams.
Gladiator may be written down most of the time but that's largely CIS/PIS. He would win this.