The Sub completes its turn and fires another torpedo. The aft torpedoes are much larger and more dangerous. They don't score a direct hit. At least they don't think they do. The explosion is enormous, and you can feel it rock the submarine (6d6x25 at 100 yards away underwater).
The demon doesn't seem to be following.
"Well even if the demon isn't going to report back for a week somebody probably saw that explosion from the surface. We should get out of here."