“Cut off their ventilation.
Use LIDAR to map out the tunnels.
Apply Thermobaric weapons GENEROUSLY.
Could work….maybe”
Screw it pump in carbon monoxide. Let them go take a permanent dirt nap. Or better yet sirin gas. Let them suffer.
Maybe pump in a hallucinogenic compound that causes psychotic breaks, so they all become paranoid and murder each other …..? I want them to suffer, too.
I say dig a trench from the Mediterranean to the nearest tunnel opening. Fill it with water, the Med will not run out of it.