The tunnel has undergone significant damage, but if the PCs are willing to wiggle around through some tight squeezes, they can hang out in the tunnel. After about half a mile, the debris becomes too impenetrable to pass.

Security guards are staffed around the caves to prevent anyone from wandering in and getting hurt. They've had a few disappearances from people who wandered in unaccompanied recently, so they're currently on high alert. PCs may be able to sneak by the guards, but they would not be able to go so far in that they would not be able to see the entrance anymore.