Thomas is surprised by how calm he is and declares that the Right Arm people can drop him off a few miles away from WICKED and let him hike in. That way it'll look like he made the trek himself in order to return.
Vince agrees and also settles on moving the rest of the Gladers and immunes to the Right Arm's headquarters.
Thomas learns how to use the device from Charlotte Chiswell. After he plants it, the device will take about an hour to render the weapons useless.
Thomas then promises he won't let himself get killed—as long as Brenda doesn't let herself get killed.