The scene where the townsfolk drive the main characters out of town. The entire time they're trying to salvage what's left of their latex faces by covering themselves with their hands. They end up looking like miserable beasts as they try to run and cover at the same time.
The flickering lights scene. one can tell how pissed off Guy-bot is about the whole ordeal, but the silver robot just... stares at himself in the mirror, trying to hold what's remaining of his mask in place.
What makes the scene all the more poignant is how it's a pretty literal case of a mirror showing the character's true self. Despite the lack of any real expressive face, you can tell that inside, Thomas-bot is being crushed inside by his true identity.
The silver robot's detonation.
Guy-bot's subsequent breakdown.
The gold robot picked up the remains of the silver robot and gathered them, making a sort of grave.
After a while of walking the desert alone, the gold robot snaps and gets on his knees, reaching for his own keypad. He can't reach it, but he keeps trying in a fit of rage, anger, and sadness.