"Justice? Who asks for justice? We make our own justice. We make it here on Arrakis—win or die. Let us not rail about justice as long as we have arms and the freedom to use them."
The CHOAM frigate, whose flight was nominally scheduled to be back to Arrakeen, had gone off the grid, putting the whole delegation in harm's way in case their position were discovered; no-one held any illusions about the Harkonnen holding back if they knew where it had gone and then blaming it all on the desert. Fortunately, Arrakis' weather control and satellite coverage was extremely rudimentary, and going off the grid wasn't an exercise in futility. Still, it's a risky political gambit - their decision to violate the terms of audit would only pay if they were to discover a smoking gun proof of Harkonnen illicit spice operations throughout the next day.
Their landing spot was a piece of flat surface atop the Habbanya Ridge. The cave system below, called Cave of Birds by the Fremen, had unknown depth and breadth as the delegation would be stopped in their tracks from exploring it the moment they landed, being surrounded by a Fremen force. They would soon learn from two auditors who'd got there first that most of the premise was off-limits to them, and the smugglers that had got the site ready for them were now in Fremen captivity, their resources seized.
The situation was tense at the spot because several Fremen leaders had gathered there and there were significant disagreements between them how to deal with the smugglers. Arrival of the CHOAM frigate only exacerbated the problem. The shield is on. Among the Fremen leaders, Stilgar seems the most amenable to the offworlders' presence, but to get out of the deadlock some negotiation and bargaining might be necessary.
The auditors would also learn that a place in the far southeastern reaches of False Wall West, a canyon called Orgiz that had once hosted a Harkonnen refinery consequently destroyed by a sandworm is alleged to be the site of the hypothesised secret mining base. Two of the auditors have left to inspect the site alongside two Fremen companions, but they haven't returned yet and - if things have gone wrong - there is a real chance they will not.