The trusting GI bot who tends Murderbot's wounds and, refusing to save itself, dies launching at the final combat bot to protect its friends.
In the geo pod, Miki gently extracts the projectiles and shrapnel from Murderbot's body, observing without envy that it has no pain and no pain sensors, and confirms it told Don Abene the truth about the SecUnit because it wanted to, not because it had to. Tender to the semiconscious Hirune and steadfast through the escape, it carries the frozen assassin Gerth and helps get the wounded aboard. It voices the quiet loneliness at its core to Murderbot: 'I never had a friend like me.' When the last combat bot breaches the fleeing shuttle, Abene orders Miki to change its priority to protecting itself; Miki rejects the order, declaring 'priority is to protect my friends,' and hurls itself across the cabin at the bot's head to give Murderbot an opening, mirroring the attack it once saw Murderbot make.
The distraction lets Murderbot drive a core cutter through the bot's brain, but in the same instant the bot crushes Miki's chest, destroying its processor and memory in one flex of its hand. Miki dies, its final act a chosen sacrifice, that its owner Abene had left it free to make; the loss devastates both Abene, who sobs over the feed, and the grieving Murderbot.
A human-form bot with a bare metal body and large opaque globe-like eyes, one hand a stump and chest scorched, in its final moment crushed and crumpled, its chest caved in.
The GI team's beloved bot; a self-aware, freely choosing being whose loyal sacrifice is the book's emotional core.