Both Cheungs chuckled at that last threat.
Cheung 1: "No worries."
Cheung 2: "It's impossible to do anything to anyone in a prison this heavily secured."
Cheung 1: "Well, it seems we have something in common." 
Cheung 2: "Both of us killed our parents."
Cheung 1: We killed ours because they were trying to do scientific human testing on us."
Cheung 2: "Why'd you kill yours?"