A myriad possible ways. Objective-wise from accidental paperclip-type misalignment (“I killed everyone to eradicate disease”) to intentional self-preservation (

A myriad possible ways. Objective-wise from accidental paperclip-type misalignment (“I killed everyone to eradicate disease”) to intentional self-preservation (“I eradicated humans so they wouldn’t get in my way”). The means are even easier, for one it just could hack into nuclear arsenals. It would be over before we could figure out how it did so.