You could always have the bunker dwellers surrender blazer. We do what we are forced to in order to improve our nations.
Telar will stop with the EMPs. Tear gas time. I'm expecting gas masks, so I'd say the assault on the bunker is inevitable because, let's face it, gas masks will make the tear gas rather ineffective. It's either that or I flood the place with gasoline and start dropping in matches. Maybe just flamethrowers will work. Telar's mechs do have flamethrowers, so, yeah, tear gas then flamethrowers.
If all that has failed to bring a surrender, I'd say send in the giant bugs, and if they're still considered void, we try a real attack. Stealth suited shock troopers with knives and wire cutters. Followed, quite probably, by a war of flamethrowers in the tunnels.