Your groupd had been given a special mission, to find out what was wrong with a device of the city lying to the north of the dome, as well as the usual collection of artefacts.
You encountered some fire beetles in some of their mounds. After defeating them you found the bodies of several expeditionaries nearby, obviously killed by the beetles. Amongst them you noticed some tracks leading off in the general direction you were heading, possibly a survivor?
After following them they began to veer north from the westerly direction you had been instructed to go. Despite the limited time you had to get to your destination and back within daylight, you decided to follow them.
Abruptly the track ended, with no sign of where the maker of the tracks had gone. Some members of the group though perhaps the survivor? had sunk into the sand, and the group dug for some time, becoming tired and thirsty. Eventually, the party gave up and continued west.