The first part of Yu Seongun’s monologue concerns how strange it is that Iser isn’t attacking. Dungeon monsters possess an instinctive hatred for humans—without exception—as if it were a fundamental rule of their existence; therefore, encountering one that doesn’t attack on sight and instead acts "friendly" is nearly impossible.
The second part refers to Jio’s "class." Yu Seongun notes that upon crossing between dimensions—from the real world into the dungeon—the class level, which Jio had deliberately lowered after emerging from the portrait (in order to blend in with people and reduce his "alien" aura), increased once again. Much like in the early chapters—before Jio merged with Giovanni—people would feel an instinctive fear of him due to this class. While this sense of unease diminished during his synchronization process with Giovanni, it spiked and then subsided again upon entering the dungeon. This is why Yu Seongun remains on guard; he does not want Jio to be further influenced by the dungeon, lest he end up becoming a "dangerous" element.

Genuinely im so confused on wtf theyre saying half the time. Like can someone explain what ehite hair is monologuing this episode?? Is the dungeon one Jio painted?? I feel dyslexic