During their discussion in Eliphas' room, Percival told him, "The 10th floor of Oxwade has no dungeon resting area because that room itself is an altar where the Eternal Flame resides."
If they headed straight for the Eternal Flame, it would take them roughly a month. However, unforeseen circumstances might force them to stay there for an extended period, which is why they needed a place to rest.
That place was Golden Land, a village inhabited by monsters.
But how could they possibly coexist with monsters?
Percival explained, "To be allowed to rest there, all you have to do is treat them kindly and listen to their requests. That will serve as a contract."
Upon reaching the 10th floor and experiencing firsthand how difficult it was to endure just the environment, Allen became acutely aware of Golden Land's importance in their expedition.
However, he never expected the request to be...
"Please kill us."