When Juuzou runs off, Wachowski assumes Tetsuro is still controlling him. Juuzou has no problem taking care of the Spitzbergen operatives sent after him, but since he never speaks we’re not entirely sure either until a very awake Tetsuro speaks to Wachowski.
Since this is after Wachowski sent Kunugi to help fight Juuzou, that leaves the old man in the wheelchair to the mercy of the kid who hacked his own sub-brain in order to control his own body. Juuzou didn’t come here to solve all of his problems for him, but to help him solve them himself.
Tetsuro offers to cooperate until Seven is defeated (keeping Juuzou out of the equation) but only if Spitzbergen ceases their terrorist activities. Wachowski regales Tetsuro with the story how how Berühren became twisted into an eternal life-support system for its four founders, and how he founded Spitzbergen to expose that rot. Only Spitzbergen also became twisted by extremists and anarchists.
For this reason, Wachowski needs Device 13, which has a setting no other Gun Slave Unit has, and which is his fail-safe against Wurzel. 13’s sacrifice will thus eliminate Berühren and with it Spitzbergen’s need to keep fighting, ushering in a new era of peace. When Tetsuro doesn’t buy it and furthermore would accept Juuzou’s sacrifice, Wachowski reveals he’s an Extended and bursts out of the suit in a a super creepy, absolutely bad-ass sequence.
As Juuzou is content to fight Kunugi (who is apparently Kronen’s senpai) and his henchmen as long as they want, Tetsuro grabs hold of his pipe dream of getting everything he wants without losing anyone he cares about. Its “beauty” is something from which he can’t turn away, so he’ll fight for that dream until his last breath—or in this case, Harmony scream.