Ruston is lying on the ground without being able to move even a bit, his body has been destroyed in multiple places which makes him a cripple. Without being able to move his body at all, he was forced to look at the two tombstones which should be Rex's parents.
It was something that he has never expected, Ruston never thought he has such a connection.
Despite feeling the malice coming from Rex the moment both of them met, he only thought that Rex felt that way because they're enemies. He never would've thought that there was more to the malice behind Rex's eyes.
While looking at the tombstones, he can't help but out a gnarly chuckle.
Only subtle crackling sounds escape his mouth due to his destroyed throat and lower muzzle, Ruston finds the situation he's in right now very surreal. It's because of his negligence that he birthed a monster that bites him from the back.