so i kinda figured out that if there are no threats on an item qeust you are likely to be ambushed, yet instead of running to the items to trigger the ambush you can just max range shoot out a brick in the wall without triggering the ambush, revealing the items in the chamber and going back to the map to reform the caravan whilest sellecting all the items that where "hidden" in the room without ever triggering the event. an option could be to trigger it when the item room takes damage.