They were very careful of falling into a trap. They took their time, moved slowly and look for every wall, every roof, every floor for a trap to be trigger by an unfortunate just taking just one wrong step there end. They said to themselves “were smart to know when see a trap a mile away. We have ingenuity to more around any trap we find. We’ll be fine, there’s nothing stopping us from getting into the treasure room. We got this in the bag!” And would have been right, if for that “one” trap. That one trap that was just too well hidden, too dark to see within the shadow, too hard to see even with the keenness of eyes. They would have made it back out the surface if they could have this “one” trap hole that was well hidden but by design out of place from everything else in this dungeon.