In silence and in dark nights with the acid rain that strips paint from their bodies, in her tiny hand crushed in his large one, shaking and squeezing too hard (for fear of letting go, for fear of the dark, for fear of the blue light of her optics that makes the drizzle sparkle so, blinking out, ending, and leaving this spark-forsaken planet truly barren); in war and in chaos and in every brush of a finger on a trigger, in the crushing connection of his fist and someone's jaw, he finds his reasons. Finds his purpose. He is Optimus Prime, and it is his duty to protect.
And Elita's is the last spark he will see extinguished.
He will die first.