In Chapter 46 Nic disappeared...
Tom held Joe on his shoulder as he walks towards the waterfall area.
As they walk, "Did you hear that?"
Tom asks Joe and Joe points to the backpack (backpack taken from Chapter 48) on his back and the weapons Tom takes 1 gun. (Joe on his body there are other hidden weapons remember he was prepared before coming underground, but all the other weapons were with Nic as he was carrying them.)
Joe carefully listens to where the sound comes from, they walk together and it appears to be rats.
Tom says, "Wow, so many rats."
Joe says, "This is not a good sign, there are dead things here."
"Don't scare me!"
Tom step on something...
Cracks... Turn... Ouch.
"Tom, are you okay?"
It seems like they drop off.
Tom responds, "Ouch my back, I can't move."
Joe says, "No choice, he takes the pills out of his pocket. Take this, it's painkillers."
Tom is surprised. "Huh, you have painkillers?"