To go after the tunnels. Or go through a whole multi story building and into the bunker underneath. I am actually the father of hypersonic weapons. Under the auspices of a range safety test, I shot a hypersonic penetrator into a dome of solid granite. Let’s just say that it got a lot of 4 star attention. Poor management caused the weapon to limp along for quite some time, and then the Russians said they had one and the race was on.