The Dungeon's floors have a large area, and it only expands further the deeper the floor you reach. For example, the first floor had a total area of 10,000 square kilometers, with the second floor reaching 14,400 sq. km., increasing by almost 50% of the previous floor's total land area!
Of course, this isn't an exact number, and it also varies from every dungeon, but the first floor of the Dungeon of Orinfeld City is exactly 10,000 sq. km. in total. As such, unless you run from one end to another, it would take at least 20 hours of leisurely walking to reach the other end. That's not taking into consideration the monsters that would further delay them while on the way.
"Pack: check; food and water: check; bullets: check; I'm ready to go!"
Aster, doing a last check right before entering, nodded his head in satisfaction. Since he's the weakest link in their group, he was reduced to support for their attempt at reaching the second floor. In short: baggage carrier!
