As I have said before I do not trust Tardust one inch! He has survived so far only by mixing half truths with lies, he would not have survived in prison or with the Mallers afterwards. He has given Riley and Burt a 3 hour run around without any success in finding Scratch and Co., they have been very patient with him and are correct to suspect that he is hiding information, since info is power. I thought B & R should have threatened Tardust with using him as Zombiebait, that would loosen his tongue for sure! They could make him run behind their truck to work up a sweat and pull him in at the last moment, he would sing like a canary, haha, no physical torture, only psychological.
Scratch is a psychopath, having no feelings for others and acting solely in her own interests. One can test young children psychologically and establish their psychopathic tendencies. Is it nature or nurture? Probably a mixture, but not everyone who has experienced terrible life events becomes warped and revengeful. We don't know that much of her background as per previous posts, but her behavioral tendencies are well established and the only way to protect normal preZA society from her would be prison or an asylum.
What hold does Ink have over Skittles? I agree that the link must be Radon Labs. I don't think he was a test subject as it would be very difficult to test genetically modifying drugs on humans without going through the ethics committee and loads of legislation, unless it was being done secretly like Porton Down chemical test on healthy British Soldiers who were not told at all what they were being exposed to and many suffered terrible long term health consequences. I don't think he met Ink in prison. don't think Skittles was a scientist at Radon but knew what Ink was doing and therefore holds the secret to stopping him. His mind is clearly very muddled and CJ had to remind him of causing the invasion of Dunbar to ensure his help.