Here is a map of the caves so far:
The three humans just encountered can tell you they came from the south (where you just came from) but they can't remember the exact path in the twists and turns. However, they can tell you that the point where they entered from the portal was at a point that climbed down and where they heard the giants (from which they fled).
The effect of the caving in of the cave in is that now the pile of rubble is low enough that you can climb over the top of it to get to the northeast side if you want. In other words, you can continue to the northeast or go back the way you came.