All but too late did I realise I had neglected to accentuate the rock tunnel. Compensated by also omitting a moored submarine. And railings. And crates. And other loading equipment.
But! Other than that....
Maybe it was built in preparation for a submersible to be invented? Therefore they're not exactly sure where to place equipment and railings and such yet?
"You have entered a large cavern. Budget issues, probably. Roll for initiative!"
Great efforts had been made to expand the cave, taming nature into the shape of a port - abandoned, it seemed, before its completion. Whatever had halted the construction was now, they concluded, in a hurry to present itself to them: the deep below them grew darker in a flash and within seconds the water heaved itself towards the rocky ceiling and onto the lower platform. With it followed a great, writhing mass that quickly scaled the wall and positioned itself between the trio and the tunnel.
The priest slumped to his knees, tearing at his ears with a scream that momentarily took Collins back to the Field Ambulance. Then, there was silence again as the padre had promptly hurled himself over the edge unto the concrete below, and death. The thing now turned to the Prussian.
Seconds passed without a sound, but it was apparent to Collins now that the barber from Stettin and the fiend of the deep were locked in the same struggle as had urged his oldest friend to meet his maker moments before. The barber was of another stock however: his visage was paling - years seemingly being ripped away from him - but if his soul was losing the fight he did not otherwise show it. There could, of course, be no victory them here. "D-dupek", the man stuttered as he drew his stiletto and leapt at the thing which, in a flurry of spinning and twisting motion, ended the threat - if it was ever that.
This is it, Collins thought to himself, accepting in full that his demise would be of his own doing. Ljung may have opened the door to the beyond, but it was he who had not walked away - and certainly not for lack of opportunities. But after all, how could he have?
The thing paused as if sharing in Collins' reflections and to his surprise he felt a complete calm. Eyeless and ever silent, somehow Collins still knew in that moment that he needn't fear it - that he mustn't fear it or what he now had to do. He smiled and rushed towards the tunnel and as the thing returned to the deep he slipped on what once was a barber from Stettin. He got up and limped onwards, cackling with laughter now; it didn't matter - none of it did. The world must burn.
Thanks for the push, @DaltonSpence!