Chester was not thrilled about things on a number of different levels. The detective wasn't doing what he had assured the larger werewolf that he would be taking care of.
In fact, things seemed to only be getting worse rather than getting any better. He knew that wasn't entirely Houston's fault but he was certain that there was more the other werewolf could be doing to make things run more smoothly.
Keith was the second one that he was annoyed at. His friend was so quick to jump at everything and do what he thought would be best rather than thinking things through like the taller werewolf did.
He knew that emotions made people do strange things but this was too much even for him. If Callum was dealing with something similar, he'd go about the situation in a completely different manner than the one that Keith choose.