Sentient 6 Lyrics

Lyric discussion by RSFB 

Cover art for Sentient 6 lyrics by Nevermore

This part is important IMO:

"Rewarded when I replicate, isolate and mutate To assimilate a fragmented plea for ego"

My interpretation is that the robot mutated in order to form an ego he in part wished to have. When that mutation happened, the robot felt "rewarded", and then proceeded to destroy humankind.