They have scars; it's a given, in Aperture. Nigel wears a scarf he found in the facility to hide the scuffs of a recent nasty incident, when he got stuck in the wires on the maintenance catwalk and struggled for hours, terrified even though he knew he couldn't suffocate.

It's a given, though when they're lounging in the quiet, Wheatley takes care to kiss his way up Nigel's neck, pulling the scarf away. It's dropped gently to the floor, left among cans of orange soda. Their test subjects are long gone. Maybe they can hear singing, in the far distance.