A collapse would not have to be total.
A partial collapse would be enough.
He looked around for something with wheels.
Near the wall was an old utility dolly, the kind used to haul boxes and equipment. Thick tires. Bent handle. A tool of brute labor. Beside it sat a low cart, half buried in dust, maybe once used to move supplies in and out.
Joe dragged the dolly free.
He loaded the C-4 onto it and unwrapped three blocks and pressed them together, molding them into a single mass. The compound was pliable, almost like clay. It stuck to itself and held its shape.
He took two blasting caps from the foam compartment and crimped them carefully into the C-4, one on each side of themass, pushing them deep enough that they wouldn't pull free but shallow enough that the shock would propagate cleanly through the explosive.
Joe twisted the leg wires together, creating a single circuit, then connected them to the firing device leads. Red to red. Black to black. The connections were solid, free of slack.
He cut a ten-foot length of det cord and pressed one end into the C-4 between the blasting caps. The cord would ensure the entire mass detonated simultaneously, not in sequence.
It was the difference between a shaped charge and a mess.
He wrapped the remaining three blocks around the det cord and molded them into the assembly, building a single unit.
Then he set the timer.
The M81 had a dial marked in minutes. He twisted it to three. Not long enough for them to organize and counter it. Not short enough to trap him on the wrong side of it. Three minutes gave him time to get clear and find cover.
He pulled the safety pin and heard the faint tick of the mechanism engaging. The spring was wound and the clock was running.
Joe paused with his hand on the dolly handle and forced his brain to ask the question it needed to ask.
If there were nuclear devices deeper in the mine, could a conventional blast set one off?
The answer was no, not the way people imagined.
A nuclear detonation was not a simple explosion. It was precision. It required a specific internal sequence, timing measured too tight for chaos. You could smash a device apart. You could detonate its conventional components and scatter material that nobody wanted scattered.
But you did not get a nuclear blast by accident.
Joe only cared about consequences.
A conventional blast in a confined tunnel would kill men. It would collapse rock. It would bury evidence. It might also turn anything nuclear into a poisoned mess.
But if his choice was poisoned mess or a city wiped out, it was not a choice.
He pushed the dolly toward the mouth of the tunnel.
The slope was still there, dropping into darkness. The air down the shaft felt colder than the air outside it, as if the mine held winter inside its lungs.
Joe positioned himself at the corner where the tunnel bent and the line of sight disappeared, then shoved the dolly forward.
The wheels clattered. The dolly started rolling down the grade, picking up speed. The ticking of the timer was audible for a moment, then swallowed by distance and stone.
He didn't watch it go.
He listened.
Clatter.
Rattle.
