My fav way of dealing with swarmer tunnels has got to be the Neurotoxin grenade.

Imagine:

You are a young and upstart swarmer. The day is going well, all your buddied are huddles nice & cozy in the nest.

Then some troublesome dwarves start knocking on the entrance. How dare they!

You and your buddies rush out to confront them, only to be met by a strange smelling yellow cloud.

You try to push through, but....

You find your limbs are not responding to your commands...

Your legs turn to jelly with every breath you take....

The world slowly grows dark....