A cinematic medium shot from behind of a lone figure in dark tactical gear and helmet, standing inside a futuristic underwater corridor. The character begins to walk forward slowly and deliberately, heading deeper into the tunnel. The corridor is dimly lit with soft blue lights and scattered reflections on metallic walls. Steam and floating particles subtly fill the air. The camera remains behind the character, with a slight tracking movement forward to create immersion. The mood is calm, tense, and resolute.