The waiting in these caverns is disturbed by slight tremors in the surrounding stone, something no Underdark dweller likes. Those who take this route more often amongst the caravan guards tell you (if asked) that this is a normal occurance though. Some volcanic activity deep below you.
When the scouts finally get you all going, the make you haste through a network of tunnels which become increasingly warmer. The air is dry and sometimes you think you can even see it waver, obscuring your seight in some of the caverns you are passing by. As are a number of Underdark creature, who suffocated while trying to find their way through this maze. The travelling takes its toll on your nerves, but after an hour or so, you safely get to the safe side of that particluar part of the route. Soon, the air cools to a normal level and after a few more hours of work, you enter a large carvern bustling with life. After getting your way past the guards, the caravan leader bides her farewell leads his lizards and trolls away. Xune tells you that this is one of the trade bazaars of Sschindylryn, a short distance away from the city itself. The latter, as you know, has no direct exit to the Underdark.