Despite Kinzie's opinion on him, it's time to save Matt Miller. Go to The Broken Shillelagh and after a short scene, you'll be transported to a new area. Here, you'll be in a top down 8-bit world where you control a tank. Shoot the other tank and bikes that appear and you'll eventually be back in 3D.
There are gates blocking your path which must be shot and destroyed. Destroy the first one and then follow the path, destroying the tanks until you get to a second gate. The towers that spawn control the tanks, similar to the portals spawning more Zin. Continue yet again to a third gate, which Zinyak will make invincible. Hold out by fighting until your tank is eventually destroyed and you go on foot.
You need to jump on the bike and start driving to the prison where Matt is being held. You have a few minutes to get there, which is more than enough time as you should ignore all enemies. The path is pretty linear as well, so there's no way you'll get lost. Once you get to the IO tower, it's time to face a choice.
Zinyak will give you a choice between a blue door and a red door. The blue door leads to you continuing to try and futilely rescue your friends, while the red door will have Zinyak free all of the humans he has kidnapped, but at the cost of your own life. Note that Zinyak is lying with the red door, so choose the blue one.
You'll now be in a text adventure game where you need to go through to free Matt. There isn't much of a threat here and no really wrong answers, as you will be able to go back and choose the correct one to advance. Once you clear the game with Matt, there will be a cutscene and the mission will be over.
