Look left, and then look right. If theres a door on either side, enter.

There doesn't seem to be doors on either side. The lines of containers go down each end. The ship must have some sort of weird series of rooms that are under the deck. There's no way a ship could be this tall and yet so short, and they usually don't store the containers under the deck.
In the direction of the green container, there's a flat wall with some warning stripes and words you can't make out from here. Towards the red container is a door.
[also small edit]