Tension inside thriller

The thriller I'm analyzing is called "Submerged" and specifically I'm analyzing tension in the opening sequence. The clip is below.
           

Submerged

At the very start of the clip (0-10 seconds) the scene is very dark, as an audience we are automatically intrigued, as we are curious to see what it is in the dark. The scene is potentially frightening as we do not know what is coming. An eerie blue light comes into shot and drifts slowly across the screen, the object behind the light is blurred and unclear, this creates tension as the viewer is eager to see what the object is and intently watches to find out. Also the music used to accompany the mysterious object is “creepy” and unnatural creating tension by adding a further sense of irregularity. The music is slow, pulsating, high pitched and alien. It creates a hostile and unsafe mood.

    


Inside the submarine it is a small space. The camera is therefore close to the crew members and we the audience are made to feel in the moment. The small size of the submarine cabin is also effective as it alerts us as to how closed off they are from the rest of the world, and if something were to go wrong they would be in danger, this adds tension to the scene. The camera cuts back to the drifting submarine, once again showing the eerie blue light with the intense audio, another reminder of their isolation. Back in the cabin one of the crew members spots an object on one of the monitors. It is unclear what the object is so we concentrate hard on the screen, inquisitive as to what’s been spotted, creating tension. The crew spot a sunken ship, this creates tension as it is foreshadowing of worse to come. We are focusing on the ship when an unknown presence bashes against the camera, the fact that we don’t know what it is again creates tension as we are intrigued as to what it might be.

One of the crew says “the electronics are down, nobody is going to hear us, everything is dead”” this creates panic and excitement as we know how far from help they are, and how dangerous their situation is, this creates more tension. The words “everything is dead is crucial as it could be more foreshadowing that the crew members are going to die..

The scene cuts to darkness and a high pitched groaning noise resonates, again the noise is alien and hostile which creates a sense of fear and unknown.