During the Vietnam war the army did experiments with tear gas tarps & leaf blowers to clear tunnel complexes. My thought is drop in some CS gas ,cover the entrance with tarps & stick in the muzzle of a couple of leaf blowers to move the gas to the Mexican side . Meanwhile someone is in a cherry picker with binoculars looking for folks bailing out of a building.
Toss in Vomiting agent Grenades to make it fun.