Added 13 minutes later
In short, in the room, Ren lights a torch from Eyr's sword, and the group rearranges into the formation listed in order from the starting character to the last:
Eyr
Kalentia
Veserod
Renold
Ilva
Alessia
And gradually (taking into account Veserod's field of vision and his position, outside of intersections, they will move three squares at a time), they head into the upper tunnel, looking for possible traps, until something interesting, unusual, or hostile comes into view. Or something unexpected happens. Or we discover another dead end.