Network Effect (The Murderbot Diaries, Bk. 5)

It calls itself Murderbot, but only when no one can hear.

It worries about the fragile human crew who've grown to trust it, but only where no one can see.

It tells itself that they're only a professional obligation, but when they're captured and an old friend from the past requires urgent assistance, Murderbot must choose between inertia and drastic action.

Drastic action it is, then.