With the deep chasm at their right hand, it takes our Heroes around 20 minutes to circle around clockwise, until they can see across the crevice to the puffball cave (area #2). From the left-behind frayed ropes and bent spikes that litter the area, it is apparent that past adventuring parties who couldn't find the secret door (at #4) attempted to climb over the void.
The returning Adventurers are expecting it, but the newcomers experience quite a shock: Approaching the westernmost point (#15) they detect a whiff of stale barbecue odor. On closer inspection, they see the aftermath of a terrible combat: The scattered remains of over a dozen Hobbets! Some of the bodies bear weapon-wounds, while others appear to have been mauled or chewed. All of the bodies are charred or burned, some of them to cinders. All of the bodies bear excessive wounds, beyond what it would take to kill an ordinary Hobbet, as though someone wanted them not just dead, but dead-dead.
It's a shock to our newbies' sanity, for sure.
At the spot marked X there is an alcove in the wall. It is full of debris and trash that has been piled into mounds that would make perfect little sleeping-nests for Hobbet-sized feral creatures. The air has a foul and rotting stench, and thousands of fleas, roaches, bedbugs, and worse scurry away from the torchlight. Scattered amidst the trash our Heroes see the glitter of many coins.
Your DM has been a little loosey-goosey about communicating the passage of time, but our Heroes have been down here for 2 hours now.
Full size image: https://photos.app.goo.gl/FYLu2ECAYGqKnJUQA