I reread it all, and I made one of my infamous quick Paint maps.
[url]
https://gyazo.com/02c3517b739aaf296f8b96f725aa1199[/url]

This is going off the descriptions you gave as GM. Just inside the entrance is the right hand wet path that everyone took, and the left hand dry.

Then there's the open area that had the cart. 

Then theres a fork, the straight path being narrower, and the other path that everyone else seemed to take, that led to the big cavern.

That cavern led south, northwest, and north. You stated the cavein occurred from the side they entered from aka east. Gerard was caught in the cavein, Marzi and Hogarth were on his side, while everyone else was in the bigger cavern.

Following the Cavein, Jasmin, Thomas, and Fren went south, while the others haven't moved from their current positions.