Jack was someone who was originally an enemy, but he gradually tried to win over Kevin and Kris's trust by showing a loyal attitude to the two men.
Jack thought that he finally won their trust when they told everything about the mysterious case they were investigating. They included him in every investigation, and he thought that the two men finally could accept him on their side.
But now when he learned the truth about Kevin and Kris trying to hide some matters from him, he was quite offended by it. He suspected that the two men couldn't trust him in the end.
The blonde glared at the pairing, and his face was plastered by the look of disappointment.
"It's not like that, Jack—"
"If it's not like that, then what, Kevin? Do you and Kris suspect me for the incident that happened in your apartment? Or even the incident that happened tonight? You suspect me for everything, right?"