This is Christopher's first memory of David.
He doesn't remember the first time he saw David, or the how he met him. Inconsequential. He remembers Taco Bell, watching Thompson punk-out and turn David's nose into burger. He remembers pulling David out behind the dumpster, trying to piece his face back together and getting blood all over his Misfits tee for his trouble. David was whining like a punk-ass bitch and Christopher was laughing.
Now he's not laughing. David isn't whining. It's not a dumpster, it's a pile of bodies and sand. It's not Thompson, it's a Hetwan. He's wearing armor, not a tee, and it's not David's nose so much as most of his upper chest.
This is Christopher's last memory of David.