When you traverse an unremarkable section of the dungeon, roll+LUCK (whoever has the lowest).
On a 10+, nothing will accost or surprise you until you enter another room/passageway.
On a 7-9, you're fine for now, but you can hear something in the darkness. Choose 1:
- you can't be surprised
- you can't be prevented from retreating
On a miss, random encounter (the GM determines what and how it approaches you).