Spoiler (click to show/hide):
With the wonky golems coming out of that house? Not that I'm going to push you, but that seems like the best way to integrate your character being able to explain Johann, and I'm going to slowly steer toward that if you don't mind.
As you head back toward the dungeon, you can detect something slightly off about it. Some careful probing with your abnormal senses says it's different. Like it's shrunk or something. Before you can stop her, Karina stealths and slips into the cavern, padding on silent boots. Rather than the headlong rush into the depths that she normally makes, Karina slowly works down all of the paths. Rather than the entrenched pockets of goblins you'd expect, they're scattered. They aren't reacting... but they probably can't see Karina. The defenses are dug, but the goblins are more interested in... not lazing about, but following little paths of insanity. Some of them are walking in a circle, their feet bloody and raw from not resting. Another has obviously finished bashing his head against a wall, his dead corpse leaking fluids.
Karina stops at one of the intersections, [so, that's not terrifying at all. We still need to check the boss room, and probably the treasure/mimic room. Anything else you can think of?] She asks you, seeming to look for both comfort and direction.